diff --git a/docs/pages/docs/editor-basics/setup.mdx b/docs/pages/docs/editor-basics/setup.mdx
index fbb8795f8..84115ddd5 100644
--- a/docs/pages/docs/editor-basics/setup.mdx
+++ b/docs/pages/docs/editor-basics/setup.mdx
@@ -32,6 +32,9 @@ type BlockNoteEditorOptions = {
     width?: number;
     class?: string;
   }) => Plugin;
+  heading?: {
+    levels?: number[];
+  };
   initialContent?: PartialBlock[];
   pasteHandler?: (context: {
     event: ClipboardEvent;
@@ -73,6 +76,8 @@ The hook takes two optional parameters:
 
 `initialContent:` The content that should be in the editor when it's created, represented as an array of [Partial Blocks](/docs/manipulating-blocks#partial-blocks).
 
+`heading`: Configuration for headings. Allows you to configure the number of levels of headings that should be available in the editor. Defaults to `[1, 2, 3]`. Configurable up to 6 levels of headings.
+
 `pasteHandler`: A function that can be used to override the default paste behavior. See [Paste Handling](/docs/advanced/paste-handling) for more.
 
 `resolveFileUrl:` Function to resolve file URLs for display/download. Useful for creating authenticated URLs or implementing custom protocols.
diff --git a/packages/core/src/blocks/HeadingBlockContent/HeadingBlockContent.ts b/packages/core/src/blocks/HeadingBlockContent/HeadingBlockContent.ts
index aa503356b..5b8d7003d 100644
--- a/packages/core/src/blocks/HeadingBlockContent/HeadingBlockContent.ts
+++ b/packages/core/src/blocks/HeadingBlockContent/HeadingBlockContent.ts
@@ -11,10 +11,13 @@ import {
 import { createDefaultBlockDOMOutputSpec } from "../defaultBlockHelpers.js";
 import { defaultProps } from "../defaultProps.js";
 import { createToggleWrapper } from "../ToggleWrapper/createToggleWrapper.js";
+import { BlockNoteEditor } from "../../editor/BlockNoteEditor.js";
+
+const HEADING_LEVELS = [1, 2, 3, 4, 5, 6] as const;
 
 export const headingPropSchema = {
   ...defaultProps,
-  level: { default: 1, values: [1, 2, 3] as const },
+  level: { default: 1, values: HEADING_LEVELS },
   isToggleable: { default: false },
 } satisfies PropSchema;
 
@@ -28,8 +31,9 @@ const HeadingBlockContent = createStronglyTypedTiptapNode({
   },
 
   addInputRules() {
+    const editor = this.options.editor as BlockNoteEditor<any, any, any>;
     return [
-      ...[1, 2, 3].map((level) => {
+      ...editor.settings.heading.levels.map((level) => {
         // Creates a heading of appropriate level when starting with "#", "##", or "###".
         return new InputRule({
           find: new RegExp(`^(#{${level}})\\s$`),
@@ -61,87 +65,46 @@ const HeadingBlockContent = createStronglyTypedTiptapNode({
   },
 
   addKeyboardShortcuts() {
-    return {
-      "Mod-Alt-1": () => {
-        const blockInfo = getBlockInfoFromSelection(this.editor.state);
-        if (
-          !blockInfo.isBlockContainer ||
-          blockInfo.blockContent.node.type.spec.content !== "inline*"
-        ) {
-          return true;
-        }
-
-        // call updateBlockCommand
-        return this.editor.commands.command(
-          updateBlockCommand(blockInfo.bnBlock.beforePos, {
-            type: "heading",
-            props: {
-              level: 1 as any,
-            },
-          }),
-        );
-      },
-      "Mod-Alt-2": () => {
-        const blockInfo = getBlockInfoFromSelection(this.editor.state);
-        if (
-          !blockInfo.isBlockContainer ||
-          blockInfo.blockContent.node.type.spec.content !== "inline*"
-        ) {
-          return true;
-        }
-
-        return this.editor.commands.command(
-          updateBlockCommand(blockInfo.bnBlock.beforePos, {
-            type: "heading",
-            props: {
-              level: 2 as any,
-            },
-          }),
-        );
-      },
-      "Mod-Alt-3": () => {
-        const blockInfo = getBlockInfoFromSelection(this.editor.state);
-        if (
-          !blockInfo.isBlockContainer ||
-          blockInfo.blockContent.node.type.spec.content !== "inline*"
-        ) {
-          return true;
-        }
-
-        return this.editor.commands.command(
-          updateBlockCommand(blockInfo.bnBlock.beforePos, {
-            type: "heading",
-            props: {
-              level: 3 as any,
-            },
-          }),
-        );
-      },
-    };
+    const editor = this.options.editor as BlockNoteEditor<any, any, any>;
+
+    return Object.fromEntries(
+      editor.settings.heading.levels.map((level) => [
+        `Mod-Alt-${level}`,
+        () => {
+          const blockInfo = getBlockInfoFromSelection(this.editor.state);
+          if (
+            !blockInfo.isBlockContainer ||
+            blockInfo.blockContent.node.type.spec.content !== "inline*"
+          ) {
+            return true;
+          }
+
+          return this.editor.commands.command(
+            updateBlockCommand(blockInfo.bnBlock.beforePos, {
+              type: "heading",
+              props: {
+                level: level as any,
+              },
+            }),
+          );
+        },
+      ]),
+    );
   },
   parseHTML() {
+    const editor = this.options.editor as BlockNoteEditor<any, any, any>;
+
     return [
       // Parse from internal HTML.
       {
         tag: "div[data-content-type=" + this.name + "]",
         contentElement: ".bn-inline-content",
       },
-      // Parse from external HTML.
-      {
-        tag: "h1",
-        attrs: { level: 1 },
-        node: "heading",
-      },
-      {
-        tag: "h2",
-        attrs: { level: 2 },
+      ...editor.settings.heading.levels.map((level) => ({
+        tag: `h${level}`,
+        attrs: { level },
         node: "heading",
-      },
-      {
-        tag: "h3",
-        attrs: { level: 3 },
-        node: "heading",
-      },
+      })),
     ];
   },
 
diff --git a/packages/core/src/editor/Block.css b/packages/core/src/editor/Block.css
index 17495ff9b..88a7c6d57 100644
--- a/packages/core/src/editor/Block.css
+++ b/packages/core/src/editor/Block.css
@@ -130,6 +130,15 @@ NESTED BLOCKS
 [data-content-type="heading"][data-level="3"] {
   --level: 1.3em;
 }
+[data-content-type="heading"][data-level="4"] {
+  --level: 1em;
+}
+[data-content-type="heading"][data-level="5"] {
+  --level: 0.9em;
+}
+[data-content-type="heading"][data-level="6"] {
+  --level: 0.8em;
+}
 
 [data-prev-level="1"] {
   --prev-level: 3em;
@@ -140,6 +149,15 @@ NESTED BLOCKS
 [data-prev-level="3"] {
   --prev-level: 1.3em;
 }
+[data-prev-level="4"] {
+  --prev-level: 1em;
+}
+[data-prev-level="5"] {
+  --prev-level: 0.9em;
+}
+[data-prev-level="6"] {
+  --prev-level: 0.8em;
+}
 
 .bn-block-outer[data-prev-type="heading"] > .bn-block > .bn-block-content {
   font-size: var(--prev-level);
diff --git a/packages/core/src/editor/BlockNoteEditor.ts b/packages/core/src/editor/BlockNoteEditor.ts
index 8008312c3..fe6812803 100644
--- a/packages/core/src/editor/BlockNoteEditor.ts
+++ b/packages/core/src/editor/BlockNoteEditor.ts
@@ -229,6 +229,18 @@ export type BlockNoteEditorOptions<
     class?: string;
   }) => Plugin;
 
+  /**
+   * Configuration for headings
+   */
+  heading?: {
+    /**
+     * The levels of headings that should be available in the editor.
+     * @note Configurable up to 6 levels of headings.
+     * @default [1, 2, 3]
+     */
+    levels?: (1 | 2 | 3 | 4 | 5 | 6)[];
+  };
+
   /**
    * The content that should be in the editor when it's created, represented as an array of partial block objects.
    */
@@ -527,6 +539,9 @@ export class BlockNoteEditor<
       headers: boolean;
     };
     codeBlock: CodeBlockOptions;
+    heading: {
+      levels: (1 | 2 | 3 | 4 | 5 | 6)[];
+    };
   };
 
   public static create<
@@ -580,6 +595,9 @@ export class BlockNoteEditor<
         supportedLanguages: options?.codeBlock?.supportedLanguages ?? {},
         createHighlighter: options?.codeBlock?.createHighlighter ?? undefined,
       },
+      heading: {
+        levels: options?.heading?.levels ?? [1, 2, 3],
+      },
     };
 
     // apply defaults
diff --git a/packages/core/src/editor/editor.css b/packages/core/src/editor/editor.css
index 3c5871b89..eb267a7b5 100644
--- a/packages/core/src/editor/editor.css
+++ b/packages/core/src/editor/editor.css
@@ -44,6 +44,9 @@ Tippy popups that are appended to document.body directly
 .bn-default-styles h1,
 .bn-default-styles h2,
 .bn-default-styles h3,
+.bn-default-styles h4,
+.bn-default-styles h5,
+.bn-default-styles h6,
 .bn-default-styles li {
   margin: 0;
   padding: 0;
diff --git a/packages/core/src/extensions/SuggestionMenu/getDefaultSlashMenuItems.ts b/packages/core/src/extensions/SuggestionMenu/getDefaultSlashMenuItems.ts
index a5f7c4bca..bcc95c83a 100644
--- a/packages/core/src/extensions/SuggestionMenu/getDefaultSlashMenuItems.ts
+++ b/packages/core/src/extensions/SuggestionMenu/getDefaultSlashMenuItems.ts
@@ -122,37 +122,6 @@ export function getDefaultSlashMenuItems<
         key: "heading_3",
         ...editor.dictionary.slash_menu.heading_3,
       },
-      {
-        onItemClick: () => {
-          insertOrUpdateBlock(editor, {
-            type: "heading",
-            props: { level: 1, isToggleable: true },
-          });
-        },
-        key: "toggle_heading",
-        ...editor.dictionary.slash_menu.toggle_heading,
-      },
-      {
-        onItemClick: () => {
-          insertOrUpdateBlock(editor, {
-            type: "heading",
-            props: { level: 2, isToggleable: true },
-          });
-        },
-
-        key: "toggle_heading_2",
-        ...editor.dictionary.slash_menu.toggle_heading_2,
-      },
-      {
-        onItemClick: () => {
-          insertOrUpdateBlock(editor, {
-            type: "heading",
-            props: { level: 3, isToggleable: true },
-          });
-        },
-        key: "toggle_heading_3",
-        ...editor.dictionary.slash_menu.toggle_heading_3,
-      },
     );
   }
 
@@ -346,6 +315,57 @@ export function getDefaultSlashMenuItems<
     });
   }
 
+  if (checkDefaultBlockTypeInSchema("heading", editor)) {
+    items.push(
+      {
+        onItemClick: () => {
+          insertOrUpdateBlock(editor, {
+            type: "heading",
+            props: { level: 1, isToggleable: true },
+          });
+        },
+        key: "toggle_heading",
+        ...editor.dictionary.slash_menu.toggle_heading,
+      },
+      {
+        onItemClick: () => {
+          insertOrUpdateBlock(editor, {
+            type: "heading",
+            props: { level: 2, isToggleable: true },
+          });
+        },
+
+        key: "toggle_heading_2",
+        ...editor.dictionary.slash_menu.toggle_heading_2,
+      },
+      {
+        onItemClick: () => {
+          insertOrUpdateBlock(editor, {
+            type: "heading",
+            props: { level: 3, isToggleable: true },
+          });
+        },
+        key: "toggle_heading_3",
+        ...editor.dictionary.slash_menu.toggle_heading_3,
+      },
+    );
+
+    editor.settings.heading.levels
+      .filter((level): level is 4 | 5 | 6 => level > 3)
+      .forEach((level) => {
+        items.push({
+          onItemClick: () => {
+            insertOrUpdateBlock(editor, {
+              type: "heading",
+              props: { level: level },
+            });
+          },
+          key: `heading_${level}`,
+          ...editor.dictionary.slash_menu[`heading_${level}`],
+        });
+      });
+  }
+
   items.push({
     onItemClick: () => {
       editor.openSuggestionMenu(":", {
diff --git a/packages/core/src/i18n/locales/ar.ts b/packages/core/src/i18n/locales/ar.ts
index ac714adb5..12ae9f698 100644
--- a/packages/core/src/i18n/locales/ar.ts
+++ b/packages/core/src/i18n/locales/ar.ts
@@ -20,23 +20,41 @@ export const ar: Dictionary = {
       aliases: ["ع3", "عنوان3", "عنوان فرعي"],
       group: "العناوين",
     },
+    heading_4: {
+      title: "عنوان 4",
+      subtext: "عنوان فرعي ثانوي صغير",
+      aliases: ["ع4", "عنوان4", "عنوان فرعي صغير"],
+      group: "العناوين الفرعية",
+    },
+    heading_5: {
+      title: "عنوان 5",
+      subtext: "عنوان فرعي صغير",
+      aliases: ["ع5", "عنوان5", "عنوان فرعي صغير"],
+      group: "العناوين الفرعية",
+    },
+    heading_6: {
+      title: "عنوان 6",
+      subtext: "أدنى مستوى للعناوين",
+      aliases: ["ع6", "عنوان6", "العنوان الفرعي الأدنى"],
+      group: "العناوين الفرعية",
+    },
     toggle_heading: {
       title: "عنوان قابل للطي 1",
       subtext: "عنوان قابل للطي لإظهار وإخفاء المحتوى",
       aliases: ["ع", "عنوان1", "ع1", "قابل للطي", "طي"],
-      group: "العناوين",
+      group: "العناوين الفرعية",
     },
     toggle_heading_2: {
       title: "عنوان قابل للطي 2",
       subtext: "عنوان فرعي قابل للطي لإظهار وإخفاء المحتوى",
       aliases: ["ع2", "عنوان2", "عنوان فرعي", "قابل للطي", "طي"],
-      group: "العناوين",
+      group: "العناوين الفرعية",
     },
     toggle_heading_3: {
       title: "عنوان قابل للطي 3",
       subtext: "عنوان فرعي ثانوي قابل للطي لإظهار وإخفاء المحتوى",
       aliases: ["ع3", "عنوان3", "عنوان فرعي", "قابل للطي", "طي"],
-      group: "العناوين",
+      group: "العناوين الفرعية",
     },
     quote: {
       title: "اقتباس",
diff --git a/packages/core/src/i18n/locales/de.ts b/packages/core/src/i18n/locales/de.ts
index 648584e05..fa97a6aeb 100644
--- a/packages/core/src/i18n/locales/de.ts
+++ b/packages/core/src/i18n/locales/de.ts
@@ -20,11 +20,29 @@ export const de: Dictionary = {
       aliases: ["h3", "überschrift3", "unterüberschrift"],
       group: "Überschriften",
     },
+    heading_4: {
+      title: "Überschrift 4",
+      subtext: "Überschrift für kleinere Unterabschnitte",
+      aliases: ["h4", "überschrift4", "unterüberschrift4"],
+      group: "Unterüberschriften",
+    },
+    heading_5: {
+      title: "Überschrift 5",
+      subtext: "Überschrift für tiefere Unterabschnitte",
+      aliases: ["h5", "überschrift5", "unterüberschrift5"],
+      group: "Unterüberschriften",
+    },
+    heading_6: {
+      title: "Überschrift 6",
+      subtext: "Überschrift auf der untersten Ebene",
+      aliases: ["h6", "überschrift6", "unterüberschrift6"],
+      group: "Unterüberschriften",
+    },
     toggle_heading: {
       title: "Aufklappbare Überschrift 1",
       subtext: "Aufklappbare Hauptebene Überschrift",
       aliases: ["h", "überschrift1", "h1", "aufklappbar", "einklappbar"],
-      group: "Überschriften",
+      group: "Unterüberschrift",
     },
     toggle_heading_2: {
       title: "Aufklappbare Überschrift 2",
@@ -36,7 +54,7 @@ export const de: Dictionary = {
         "aufklappbar",
         "einklappbar",
       ],
-      group: "Überschriften",
+      group: "Unterüberschriften",
     },
     toggle_heading_3: {
       title: "Aufklappbare Überschrift 3",
@@ -48,7 +66,7 @@ export const de: Dictionary = {
         "aufklappbar",
         "einklappbar",
       ],
-      group: "Überschriften",
+      group: "Unterüberschriften",
     },
     quote: {
       title: "Zitat",
diff --git a/packages/core/src/i18n/locales/en.ts b/packages/core/src/i18n/locales/en.ts
index 0557e4114..78f5d83bb 100644
--- a/packages/core/src/i18n/locales/en.ts
+++ b/packages/core/src/i18n/locales/en.ts
@@ -18,23 +18,41 @@ export const en = {
       aliases: ["h3", "heading3", "subheading"],
       group: "Headings",
     },
+    heading_4: {
+      title: "Heading 4",
+      subtext: "Minor subsection heading",
+      aliases: ["h4", "heading4", "subheading4"],
+      group: "Subheadings",
+    },
+    heading_5: {
+      title: "Heading 5",
+      subtext: "Small subsection heading",
+      aliases: ["h5", "heading5", "subheading5"],
+      group: "Subheadings",
+    },
+    heading_6: {
+      title: "Heading 6",
+      subtext: "Lowest-level heading",
+      aliases: ["h6", "heading6", "subheading6"],
+      group: "Subheadings",
+    },
     toggle_heading: {
       title: "Toggle Heading 1",
       subtext: "Toggleable top-level heading",
       aliases: ["h", "heading1", "h1", "collapsable"],
-      group: "Headings",
+      group: "Subheadings",
     },
     toggle_heading_2: {
       title: "Toggle Heading 2",
       subtext: "Toggleable key section heading",
       aliases: ["h2", "heading2", "subheading", "collapsable"],
-      group: "Headings",
+      group: "Subheadings",
     },
     toggle_heading_3: {
       title: "Toggle Heading 3",
       subtext: "Toggleable subsection and group heading",
       aliases: ["h3", "heading3", "subheading", "collapsable"],
-      group: "Headings",
+      group: "Subheadings",
     },
     quote: {
       title: "Quote",
diff --git a/packages/core/src/i18n/locales/es.ts b/packages/core/src/i18n/locales/es.ts
index eb4f8d171..66af2f092 100644
--- a/packages/core/src/i18n/locales/es.ts
+++ b/packages/core/src/i18n/locales/es.ts
@@ -20,23 +20,41 @@ export const es: Dictionary = {
       aliases: ["h3", "encabezado3", "subencabezado"],
       group: "Encabezados",
     },
+    heading_4: {
+      title: "Encabezado 4",
+      subtext: "Encabezado de subsección menor",
+      aliases: ["h4", "encabezado4", "subencabezado4"],
+      group: "Subencabezados",
+    },
+    heading_5: {
+      title: "Encabezado 5",
+      subtext: "Encabezado de subsección pequeña",
+      aliases: ["h5", "encabezado5", "subencabezado5"],
+      group: "Subencabezados",
+    },
+    heading_6: {
+      title: "Encabezado 6",
+      subtext: "Encabezado de nivel más bajo",
+      aliases: ["h6", "encabezado6", "subencabezado6"],
+      group: "Subencabezados",
+    },
     toggle_heading: {
       title: "Encabezado Plegable 1",
       subtext: "Encabezado de primer nivel que se puede plegar",
       aliases: ["h", "encabezado1", "h1", "plegable", "contraible"],
-      group: "Encabezados",
+      group: "Subencabezados",
     },
     toggle_heading_2: {
       title: "Encabezado Plegable 2",
       subtext: "Encabezado de sección principal que se puede plegar",
       aliases: ["h2", "encabezado2", "subencabezado", "plegable", "contraible"],
-      group: "Encabezados",
+      group: "Subencabezados",
     },
     toggle_heading_3: {
       title: "Encabezado Plegable 3",
       subtext: "Encabezado de subsección y grupo que se puede plegar",
       aliases: ["h3", "encabezado3", "subencabezado", "plegable", "contraible"],
-      group: "Encabezados",
+      group: "Subencabezados",
     },
     quote: {
       title: "Cita",
diff --git a/packages/core/src/i18n/locales/fr.ts b/packages/core/src/i18n/locales/fr.ts
index 64e3cc644..b5cc28b1a 100644
--- a/packages/core/src/i18n/locales/fr.ts
+++ b/packages/core/src/i18n/locales/fr.ts
@@ -21,12 +21,30 @@ export const fr: Dictionary = {
       aliases: ["h3", "titre3", "sous-titre"],
       group: "Titres",
     },
+    heading_4: {
+      title: "Titre 4",
+      subtext: "Titre de sous‑section mineure",
+      aliases: ["h4", "titre4", "sous‑titre4"],
+      group: "Sous-titres",
+    },
+    heading_5: {
+      title: "Titre 5",
+      subtext: "Titre de sous-section mineure",
+      aliases: ["h5", "titre5", "sous-titre5"],
+      group: "Sous-titres",
+    },
+    heading_6: {
+      title: "Titre 6",
+      subtext: "Titre de niveau le plus bas",
+      aliases: ["h6", "titre6", "sous-titre6"],
+      group: "Sous-titres",
+    },
     toggle_heading: {
       title: "Titre Repliable 1",
       subtext:
         "Titre de premier niveau qui peut être replié pour masquer son contenu",
       aliases: ["h", "titre1", "h1", "repliable", "masquable", "déroulant"],
-      group: "Titres",
+      group: "Sous-titres",
     },
     toggle_heading_2: {
       title: "Titre Repliable 2",
@@ -39,7 +57,7 @@ export const fr: Dictionary = {
         "masquable",
         "déroulant",
       ],
-      group: "Titres",
+      group: "Sous-titres",
     },
     toggle_heading_3: {
       title: "Titre Repliable 3",
@@ -53,7 +71,7 @@ export const fr: Dictionary = {
         "masquable",
         "déroulant",
       ],
-      group: "Titres",
+      group: "Sous-titres",
     },
     quote: {
       title: "Citation",
diff --git a/packages/core/src/i18n/locales/hr.ts b/packages/core/src/i18n/locales/hr.ts
index 8adf918fa..74527a60c 100644
--- a/packages/core/src/i18n/locales/hr.ts
+++ b/packages/core/src/i18n/locales/hr.ts
@@ -20,23 +20,41 @@ export const hr: Dictionary = {
       aliases: ["h3", "naslov3", "podnaslov"],
       group: "Naslovi",
     },
+    heading_4: {
+      title: "Naslov 4",
+      subtext: "Manji naslov podpoglavlja",
+      aliases: ["h4", "naslov4", "podnaslov4"],
+      group: "Podnaslovi",
+    },
+    heading_5: {
+      title: "Naslov 5",
+      subtext: "Mali naslov podpoglavlja",
+      aliases: ["h5", "naslov5", "podnaslov5"],
+      group: "Podnaslovi",
+    },
+    heading_6: {
+      title: "Naslov 6",
+      subtext: "Naslov najniže razine",
+      aliases: ["h6", "naslov6", "podnaslov6"],
+      group: "Podnaslovi",
+    },
     toggle_heading: {
       title: "Proširivi Naslov 1",
       subtext: "Proširivi glavni naslov",
       aliases: ["h", "naslov1", "h1", "proširivi"],
-      group: "Naslovi",
+      group: "Podnaslovi",
     },
     toggle_heading_2: {
       title: "Proširivi Naslov 2",
       subtext: "Proširivi naslov poglavlja",
       aliases: ["h2", "naslov2", "podnaslov", "proširivi"],
-      group: "Naslovi",
+      group: "Podnaslovi",
     },
     toggle_heading_3: {
       title: "Proširivi Naslov 3",
       subtext: "Proširivi naslov podpoglavlja",
       aliases: ["h3", "naslov3", "podnaslov", "proširivi"],
-      group: "Naslovi",
+      group: "Podnaslovi",
     },
     quote: {
       title: "Citat",
diff --git a/packages/core/src/i18n/locales/is.ts b/packages/core/src/i18n/locales/is.ts
index add3180b5..e0d08db73 100644
--- a/packages/core/src/i18n/locales/is.ts
+++ b/packages/core/src/i18n/locales/is.ts
@@ -20,12 +20,30 @@ export const is: Dictionary = {
       aliases: ["h3", "fyrirsogn3", "undirfyrirsogn"],
       group: "Fyrirsagnir",
     },
+    heading_4: {
+      title: "Fyrirsögn 4",
+      subtext: "Titill fyrir minni undirhluta",
+      aliases: ["h4", "fyrirsogn4", "undirfyrirsogn4"],
+      group: "Undirfyrirsagnir",
+    },
+    heading_5: {
+      title: "Fyrirsögn 5",
+      subtext: "Titill fyrir litla undirkafla",
+      aliases: ["h5", "fyrirsogn5", "undirfyrirsogn5"],
+      group: "Undirfyrirsagnir",
+    },
+    heading_6: {
+      title: "Fyrirsögn 6",
+      subtext: "Titill á lægsta stigi",
+      aliases: ["h6", "fyrirsogn6", "undirfyrirsogn6"],
+      group: "Undirfyrirsagnir",
+    },
     toggle_heading: {
       title: "Fellanleg Fyrirsögn 1",
       subtext:
         "Fellanleg efsta fyrirsögn sem hægt er að sýna eða fela innihald",
       aliases: ["h", "fyrirsogn1", "h1", "fellanleg", "fellanlegt"],
-      group: "Fyrirsagnir",
+      group: "Undirfyrirsagnir",
     },
     toggle_heading_2: {
       title: "Fellanleg Fyrirsögn 2",
@@ -38,7 +56,7 @@ export const is: Dictionary = {
         "fellanleg",
         "fellanlegt",
       ],
-      group: "Fyrirsagnir",
+      group: "Undirfyrirsagnir",
     },
     toggle_heading_3: {
       title: "Fellanleg Fyrirsögn 3",
@@ -51,7 +69,7 @@ export const is: Dictionary = {
         "fellanleg",
         "fellanlegt",
       ],
-      group: "Fyrirsagnir",
+      group: "Undirfyrirsagnir",
     },
     quote: {
       title: "Tilvitnun",
diff --git a/packages/core/src/i18n/locales/it.ts b/packages/core/src/i18n/locales/it.ts
index 7b7b03be8..cba938b4c 100644
--- a/packages/core/src/i18n/locales/it.ts
+++ b/packages/core/src/i18n/locales/it.ts
@@ -20,12 +20,30 @@ export const it: Dictionary = {
       aliases: ["h3", "intestazione3", "sottotitolo"],
       group: "Intestazioni",
     },
+    heading_4: {
+      title: "Intestazione 4",
+      subtext: "Intestazione di sottosezione minore",
+      aliases: ["h4", "intestazione4", "sottotitolo4"],
+      group: "Sottotitoli",
+    },
+    heading_5: {
+      title: "Intestazione 5",
+      subtext: "Intestazione di sottosezione minore",
+      aliases: ["h5", "intestazione5", "sottotitolo5"],
+      group: "Sottotitoli",
+    },
+    heading_6: {
+      title: "Intestazione 6",
+      subtext: "Intestazione di livello più basso",
+      aliases: ["h6", "intestazione6", "sottotitolo6"],
+      group: "Sottotitoli",
+    },
     toggle_heading: {
       title: "Intestazione Espandibile 1",
       subtext:
         "Intestazione di primo livello che può essere espansa o compressa per mostrare il contenuto",
       aliases: ["h", "intestazione1", "h1", "espandibile", "comprimibile"],
-      group: "Intestazioni",
+      group: "Sottotitoli",
     },
     toggle_heading_2: {
       title: "Intestazione Espandibile 2",
@@ -38,7 +56,7 @@ export const it: Dictionary = {
         "espandibile",
         "comprimibile",
       ],
-      group: "Intestazioni",
+      group: "Sottotitoli",
     },
     toggle_heading_3: {
       title: "Intestazione Espandibile 3",
@@ -51,7 +69,7 @@ export const it: Dictionary = {
         "espandibile",
         "comprimibile",
       ],
-      group: "Intestazioni",
+      group: "Sottotitoli",
     },
     quote: {
       title: "Citazione",
diff --git a/packages/core/src/i18n/locales/ja.ts b/packages/core/src/i18n/locales/ja.ts
index 12b2d1e88..3bd6ff47f 100644
--- a/packages/core/src/i18n/locales/ja.ts
+++ b/packages/core/src/i18n/locales/ja.ts
@@ -20,11 +20,29 @@ export const ja: Dictionary = {
       aliases: ["h3", "見出し3", "subheading", "小見出し"],
       group: "見出し",
     },
+    heading_4: {
+      title: "見出し４",
+      subtext: "小さなサブセクションの見出しに使用",
+      aliases: ["h4", "見出し4", "subheading4", "小見出し4"],
+      group: "サブ見出し",
+    },
+    heading_5: {
+      title: "見出し５",
+      subtext: "小さなサブセクションの見出しに使用",
+      aliases: ["h5", "見出し5", "subheading5", "小見出し5"],
+      group: "サブ見出し",
+    },
+    heading_6: {
+      title: "見出し６",
+      subtext: "最下位レベルの見出しに使用",
+      aliases: ["h6", "見出し6", "subheading6", "小見出し6"],
+      group: "サブ見出し",
+    },
     toggle_heading: {
       title: "折りたたみ見出し１",
       subtext: "内容の表示/非表示が切り替え可能なトップレベルの見出し",
       aliases: ["h", "見出し１", "h1", "大見出し", "折りたたみ", "トグル"],
-      group: "見出し",
+      group: "サブ見出し",
     },
     toggle_heading_2: {
       title: "折りたたみ見出し２",
@@ -37,7 +55,7 @@ export const ja: Dictionary = {
         "折りたたみ",
         "トグル",
       ],
-      group: "見出し",
+      group: "サブ見出し",
     },
     toggle_heading_3: {
       title: "折りたたみ見出し３",
@@ -50,7 +68,7 @@ export const ja: Dictionary = {
         "折りたたみ",
         "トグル",
       ],
-      group: "見出し",
+      group: "サブ見出し",
     },
     quote: {
       title: "引用",
diff --git a/packages/core/src/i18n/locales/ko.ts b/packages/core/src/i18n/locales/ko.ts
index 5f36b9de4..dc13c893c 100644
--- a/packages/core/src/i18n/locales/ko.ts
+++ b/packages/core/src/i18n/locales/ko.ts
@@ -20,6 +20,24 @@ export const ko: Dictionary = {
       aliases: ["h3", "제목3", "subheading"],
       group: "제목",
     },
+    heading_4: {
+      title: "제목4",
+      subtext: "하위 소단락 제목",
+      aliases: ["h4", "제목4", "소제목4"],
+      group: "소제목",
+    },
+    heading_5: {
+      title: "제목5",
+      subtext: "작은 하위 섹션 제목",
+      aliases: ["h5", "제목5", "소제목5"],
+      group: "소제목",
+    },
+    heading_6: {
+      title: "제목6",
+      subtext: "가장 하위 수준 제목",
+      aliases: ["h6", "제목6", "소제목6"],
+      group: "소제목",
+    },
     toggle_heading: {
       title: "접을 수 있는 제목1",
       subtext: "내용을 표시하거나 숨길 수 있는 섹션 제목(대)",
@@ -30,13 +48,13 @@ export const ko: Dictionary = {
       title: "접을 수 있는 제목2",
       subtext: "내용을 표시하거나 숨길 수 있는 섹션 제목(중)",
       aliases: ["h2", "제목2", "중제목", "접기", "토글"],
-      group: "제목",
+      group: "소제목",
     },
     toggle_heading_3: {
       title: "접을 수 있는 제목3",
       subtext: "내용을 표시하거나 숨길 수 있는 섹션 제목(소)",
       aliases: ["h3", "제목3", "subheading", "접기", "토글"],
-      group: "제목",
+      group: "소제목",
     },
     quote: {
       title: "인용",
diff --git a/packages/core/src/i18n/locales/nl.ts b/packages/core/src/i18n/locales/nl.ts
index 951c965fc..923026e83 100644
--- a/packages/core/src/i18n/locales/nl.ts
+++ b/packages/core/src/i18n/locales/nl.ts
@@ -20,24 +20,42 @@ export const nl: Dictionary = {
       aliases: ["h3", "kop3", "subkop"],
       group: "Koppen",
     },
+    heading_4: {
+      title: "Kop 4",
+      subtext: "Gebruikt voor kleinere subsecties",
+      aliases: ["h4", "kop4", "subkop4"],
+      group: "Subkoppen",
+    },
+    heading_5: {
+      title: "Kop 5",
+      subtext: "Gebruikt voor kleinere subsecties",
+      aliases: ["h5", "kop5", "subkop5"],
+      group: "Subkoppen",
+    },
+    heading_6: {
+      title: "Kop 6",
+      subtext: "Gebruikt voor koppen op het laagste niveau",
+      aliases: ["h6", "kop6", "subkop6"],
+      group: "Subkoppen",
+    },
     toggle_heading: {
       title: "Uitklapbare Kop 1",
       subtext: "Hoofdkop die kan worden uit- en ingeklapt om inhoud te tonen",
       aliases: ["h", "kop1", "h1", "uitklapbaar", "inklapbaar"],
-      group: "Koppen",
+      group: "Subkoppen",
     },
     toggle_heading_2: {
       title: "Uitklapbare Kop 2",
       subtext: "Sectiekop die kan worden uit- en ingeklapt om inhoud te tonen",
       aliases: ["h2", "kop2", "subkop", "uitklapbaar", "inklapbaar"],
-      group: "Koppen",
+      group: "Subkoppen",
     },
     toggle_heading_3: {
       title: "Uitklapbare Kop 3",
       subtext:
         "Subsectiekop die kan worden uit- en ingeklapt om inhoud te tonen",
       aliases: ["h3", "kop3", "subkop", "uitklapbaar", "inklapbaar"],
-      group: "Koppen",
+      group: "Subkoppen",
     },
     quote: {
       title: "Citaat",
diff --git a/packages/core/src/i18n/locales/no.ts b/packages/core/src/i18n/locales/no.ts
index cc0b3713d..e6c661664 100644
--- a/packages/core/src/i18n/locales/no.ts
+++ b/packages/core/src/i18n/locales/no.ts
@@ -20,11 +20,29 @@ export const no: Dictionary = {
       aliases: ["h3", "overskrift3", "underoverskrift"],
       group: "Overskrifter",
     },
+    heading_4: {
+      title: "Overskrift 4",
+      subtext: "Underoverskrift for mindre underseksjoner",
+      aliases: ["h4", "overskrift4", "underoverskrift4"],
+      group: "Underoverskrifter",
+    },
+    heading_5: {
+      title: "Overskrift 5",
+      subtext: "Overskrift for mindre underseksjoner",
+      aliases: ["h5", "overskrift5", "underoverskrift5"],
+      group: "Underoverskrifter",
+    },
+    heading_6: {
+      title: "Overskrift 6",
+      subtext: "Overskrift på laveste nivå",
+      aliases: ["h6", "overskrift6", "underoverskrift6"],
+      group: "Underoverskrifter",
+    },
     toggle_heading: {
       title: "Sammenleggbar Overskrift 1",
       subtext: "Toppnivåoverskrift som kan vises eller skjules",
       aliases: ["h", "overskrift1", "h1", "sammenleggbar", "toggle"],
-      group: "Overskrifter",
+      group: "Underoverskrifter",
     },
     toggle_heading_2: {
       title: "Sammenleggbar Overskrift 2",
@@ -36,7 +54,7 @@ export const no: Dictionary = {
         "sammenleggbar",
         "toggle",
       ],
-      group: "Overskrifter",
+      group: "Underoverskrifter",
     },
     toggle_heading_3: {
       title: "Sammenleggbar Overskrift 3",
@@ -48,7 +66,7 @@ export const no: Dictionary = {
         "sammenleggbar",
         "toggle",
       ],
-      group: "Overskrifter",
+      group: "Underoverskrifter",
     },
     quote: {
       title: "Sitat",
diff --git a/packages/core/src/i18n/locales/pl.ts b/packages/core/src/i18n/locales/pl.ts
index cc5117448..8684c6a91 100644
--- a/packages/core/src/i18n/locales/pl.ts
+++ b/packages/core/src/i18n/locales/pl.ts
@@ -20,23 +20,41 @@ export const pl: Dictionary = {
       aliases: ["h3", "naglowek3", "podnaglowek"],
       group: "Nagłówki",
     },
+    heading_4: {
+      title: "Nagłówek 4",
+      subtext: "Nagłówek mniejszej podsekcji",
+      aliases: ["h4", "naglowek4", "podnaglowek4"],
+      group: "Podnagłówki",
+    },
+    heading_5: {
+      title: "Nagłówek 5",
+      subtext: "Nagłówek mniejszej podsekcji",
+      aliases: ["h5", "naglowek5", "podnaglowek5"],
+      group: "Podnagłówki",
+    },
+    heading_6: {
+      title: "Nagłówek 6",
+      subtext: "Nagłówek najniższego poziomu",
+      aliases: ["h6", "naglowek6", "podnaglowek6"],
+      group: "Podnagłówki",
+    },
     toggle_heading: {
       title: "Nagłówek rozwijany 1",
       subtext: "Rozwijany nagłówek najwyższego poziomu",
       aliases: ["h", "naglowek1", "h1", "rozwijany"],
-      group: "Nagłówki",
+      group: "Podnagłówki",
     },
     toggle_heading_2: {
       title: "Nagłówek rozwijany 2",
       subtext: "Rozwijany nagłówek dla kluczowych sekcji",
       aliases: ["h2", "naglowek2", "podnaglowek", "rozwijany"],
-      group: "Nagłówki",
+      group: "Podnagłówki",
     },
     toggle_heading_3: {
       title: "Nagłówek rozwijany 3",
       subtext: "Rozwijany nagłówek dla podsekcji i grup",
       aliases: ["h3", "naglowek3", "podnaglowek", "rozwijany"],
-      group: "Nagłówki",
+      group: "Podnagłówki",
     },
     quote: {
       title: "Cytat",
diff --git a/packages/core/src/i18n/locales/pt.ts b/packages/core/src/i18n/locales/pt.ts
index 5c9e035c0..a10c5ec3a 100644
--- a/packages/core/src/i18n/locales/pt.ts
+++ b/packages/core/src/i18n/locales/pt.ts
@@ -20,23 +20,41 @@ export const pt: Dictionary = {
       aliases: ["h3", "titulo3", "subtitulo"],
       group: "Títulos",
     },
+    heading_4: {
+      title: "Título 4",
+      subtext: "Usado para subseções menores",
+      aliases: ["h4", "titulo4", "subtitulo4"],
+      group: "Subtítulos",
+    },
+    heading_5: {
+      title: "Título 5",
+      subtext: "Usado para títulos de subseções pequenas",
+      aliases: ["h5", "titulo5", "subtitulo5"],
+      group: "Subtítulos",
+    },
+    heading_6: {
+      title: "Título 6",
+      subtext: "Usado para títulos de nível mais baixo",
+      aliases: ["h6", "titulo6", "subtitulo6"],
+      group: "Subtítulos",
+    },
     toggle_heading: {
       title: "Título Expansível",
       subtext: "Título expansível de nível superior",
       aliases: ["h", "titulo1", "h1", "expansível"],
-      group: "Títulos",
+      group: "Subtítulos",
     },
     toggle_heading_2: {
       title: "Título Expansível 2",
       subtext: "Título expansível para seções principais",
       aliases: ["h2", "titulo2", "subtitulo", "expansível"],
-      group: "Títulos",
+      group: "Subtítulos",
     },
     toggle_heading_3: {
       title: "Título Expansível 3",
       subtext: "Título expansível para subseções e títulos de grupo",
       aliases: ["h3", "titulo3", "subtitulo", "expansível"],
-      group: "Títulos",
+      group: "Subtítulos",
     },
     quote: {
       title: "Citação",
diff --git a/packages/core/src/i18n/locales/ru.ts b/packages/core/src/i18n/locales/ru.ts
index 813b5b517..e7f9f19e0 100644
--- a/packages/core/src/i18n/locales/ru.ts
+++ b/packages/core/src/i18n/locales/ru.ts
@@ -20,11 +20,29 @@ export const ru: Dictionary = {
       aliases: ["h3", "heading3", "subheading", "заголовок3", "подзаголовок"],
       group: "Заголовки",
     },
+    heading_4: {
+      title: "Заголовок 4 уровня",
+      subtext: "Используется для более мелких подразделов",
+      aliases: ["h4", "heading4", "subheading4", "заголовок4", "подзаголовок4"],
+      group: "Подзаголовки",
+    },
+    heading_5: {
+      title: "Заголовок 5 уровня",
+      subtext: "Используется для заголовков небольших подразделов",
+      aliases: ["h5", "heading5", "subheading5", "заголовок5", "подзаголовок5"],
+      group: "Подзаголовки",
+    },
+    heading_6: {
+      title: "Заголовок 6 уровня",
+      subtext: "Используется для заголовков самого низкого уровня",
+      aliases: ["h6", "heading6", "subheading6", "заголовок6", "подзаголовок6"],
+      group: "Подзаголовки",
+    },
     toggle_heading: {
       title: "Сворачиваемый заголовок 1 уровня",
       subtext: "Заголовок верхнего уровня, который можно свернуть/развернуть",
       aliases: ["h", "heading1", "h1", "заголовок1", "сворачиваемый"],
-      group: "Заголовки",
+      group: "Подзаголовки",
     },
     toggle_heading_2: {
       title: "Сворачиваемый заголовок 2 уровня",
@@ -38,7 +56,7 @@ export const ru: Dictionary = {
         "подзаголовок",
         "сворачиваемый",
       ],
-      group: "Заголовки",
+      group: "Подзаголовки",
     },
     toggle_heading_3: {
       title: "Сворачиваемый заголовок 3 уровня",
@@ -52,7 +70,7 @@ export const ru: Dictionary = {
         "подзаголовок",
         "сворачиваемый",
       ],
-      group: "Заголовки",
+      group: "Подзаголовки",
     },
     quote: {
       title: "Цитата",
diff --git a/packages/core/src/i18n/locales/sk.ts b/packages/core/src/i18n/locales/sk.ts
index 1791bbac1..8fc616758 100644
--- a/packages/core/src/i18n/locales/sk.ts
+++ b/packages/core/src/i18n/locales/sk.ts
@@ -18,23 +18,41 @@ export const sk = {
       aliases: ["h3", "nadpis3", "podnadpis"],
       group: "Nadpisy",
     },
+    heading_4: {
+      title: "Nadpis 4",
+      subtext: "Podsekcia alebo skupinový nadpis",
+      aliases: ["h4", "nadpis4", "podnadpis"],
+      group: "Podnáslovi",
+    },
+    heading_5: {
+      title: "Nadpis 5",
+      subtext: "Podsekcia alebo skupinový nadpis",
+      aliases: ["h5", "nadpis5", "podnadpis"],
+      group: "Podnáslovi",
+    },
+    heading_6: {
+      title: "Nadpis 6",
+      subtext: "Podsekcia alebo skupinový nadpis",
+      aliases: ["h6", "nadpis6", "podnadpis"],
+      group: "Podnáslovi",
+    },
     toggle_heading: {
       title: "Rozbaľovací Nadpis 1",
       subtext: "Rozbaľovací nadpis najvyššej úrovne",
       aliases: ["h", "nadpis1", "h1", "rozbaľovací"],
-      group: "Nadpisy",
+      group: "Podnáslovi",
     },
     toggle_heading_2: {
       title: "Rozbaľovací Nadpis 2",
       subtext: "Rozbaľovací kľúčový nadpis sekcie",
       aliases: ["h2", "nadpis2", "podnadpis", "rozbaľovací"],
-      group: "Nadpisy",
+      group: "Podnáslovi",
     },
     toggle_heading_3: {
       title: "Rozbaľovací Nadpis 3",
       subtext: "Rozbaľovací nadpis podsekcie alebo skupiny",
       aliases: ["h3", "nadpis3", "podnadpis", "rozbaľovací"],
-      group: "Nadpisy",
+      group: "Podnáslovi",
     },
     quote: {
       title: "Citát",
diff --git a/packages/core/src/i18n/locales/uk.ts b/packages/core/src/i18n/locales/uk.ts
index a9d81026c..c44c4c198 100644
--- a/packages/core/src/i18n/locales/uk.ts
+++ b/packages/core/src/i18n/locales/uk.ts
@@ -20,23 +20,41 @@ export const uk: Dictionary = {
       aliases: ["h3", "heading3", "subheading", "заголовок3"],
       group: "Заголовки",
     },
+    heading_4: {
+      title: "Заголовок 4",
+      subtext: "Використовується для менших підрозділів",
+      aliases: ["h4", "heading4", "subheading4", "заголовок4"],
+      group: "Підзаголовки",
+    },
+    heading_5: {
+      title: "Заголовок 5",
+      subtext: "Використовується для заголовків менших підрозділів",
+      aliases: ["h5", "heading5", "subheading5", "заголовок5", "підзаголовок5"],
+      group: "Підзаголовки",
+    },
+    heading_6: {
+      title: "Заголовок 6",
+      subtext: "Використовується для заголовків найнижчого рівня",
+      aliases: ["h6", "heading6", "subheading6", "заголовок6", "підзаголовок6"],
+      group: "Підзаголовки",
+    },
     toggle_heading: {
       title: "Розгортаємий заголовок 1",
       subtext: "Розгортаємий заголовок найвищого рівня",
       aliases: ["h", "heading1", "h1", "заголовок1", "розгортаємий"],
-      group: "Заголовки",
+      group: "Підзаголовки",
     },
     toggle_heading_2: {
       title: "Розгортаємий заголовок 2",
       subtext: "Розгортаємий основний заголовок розділу",
       aliases: ["h2", "heading2", "subheading", "заголовок2", "розгортаємий"],
-      group: "Заголовки",
+      group: "Підзаголовки",
     },
     toggle_heading_3: {
       title: "Розгортаємий заголовок 3",
       subtext: "Розгортаємий підзаголовок і груповий заголовок",
       aliases: ["h3", "heading3", "subheading", "заголовок3", "розгортаємий"],
-      group: "Заголовки",
+      group: "Підзаголовки",
     },
     quote: {
       title: "Цитата",
diff --git a/packages/core/src/i18n/locales/vi.ts b/packages/core/src/i18n/locales/vi.ts
index 4107d9d67..12f005b4e 100644
--- a/packages/core/src/i18n/locales/vi.ts
+++ b/packages/core/src/i18n/locales/vi.ts
@@ -20,23 +20,41 @@ export const vi: Dictionary = {
       aliases: ["h3", "tieude3", "tieudephu"],
       group: "Tiêu đề",
     },
+    heading_4: {
+      title: "Tiêu đề H4",
+      subtext: "Sử dụng cho tiêu đề phụ nhỏ hơn",
+      aliases: ["h4", "tieude4", "tieudephu4"],
+      group: "Tiêu đề phụ",
+    },
+    heading_5: {
+      title: "Tiêu đề H5",
+      subtext: "Sử dụng cho tiêu đề phụ nhỏ hơn",
+      aliases: ["h5", "tieude5", "tieudephu5"],
+      group: "Tiêu đề phụ",
+    },
+    heading_6: {
+      title: "Tiêu đề H6",
+      subtext: "Sử dụng cho tiêu đề cấp thấp nhất",
+      aliases: ["h6", "tieude6", "tieudephu6"],
+      group: "Tiêu đề phụ",
+    },
     toggle_heading: {
       title: "Tiêu đề có thể thu gọn H1",
       subtext: "Tiêu đề cấp cao nhất có thể thu gọn",
       aliases: ["h", "tieude1", "dd1", "thugon"],
-      group: "Tiêu đề",
+      group: "Tiêu đề phụ",
     },
     toggle_heading_2: {
       title: "Tiêu đề có thể thu gọn H2",
       subtext: "Tiêu đề cho các phần chính có thể thu gọn",
       aliases: ["h2", "tieude2", "tieudephu", "thugon"],
-      group: "Tiêu đề",
+      group: "Tiêu đề phụ",
     },
     toggle_heading_3: {
       title: "Tiêu đề có thể thu gọn H3",
       subtext: "Tiêu đề cho phụ đề và tiêu đề nhóm có thể thu gọn",
       aliases: ["h3", "tieude3", "tieudephu", "thugon"],
-      group: "Tiêu đề",
+      group: "Tiêu đề phụ",
     },
     quote: {
       title: "Trích dẫn",
diff --git a/packages/core/src/i18n/locales/zh-tw.ts b/packages/core/src/i18n/locales/zh-tw.ts
index 3cc92f9f3..91a86c1e6 100644
--- a/packages/core/src/i18n/locales/zh-tw.ts
+++ b/packages/core/src/i18n/locales/zh-tw.ts
@@ -20,11 +20,29 @@ export const zhTW: Dictionary = {
       aliases: ["h3", "heading3", "subheading", "標題", "三級標題"],
       group: "標題",
     },
+    heading_4: {
+      title: "四級標題",
+      subtext: "用於小節和分組標題",
+      aliases: ["h4", "heading4", "subheading", "標題", "四級標題"],
+      group: "副標題",
+    },
+    heading_5: {
+      title: "五級標題",
+      subtext: "用於小節和分組標題",
+      aliases: ["h5", "heading5", "subheading", "標題", "五級標題"],
+      group: "副標題",
+    },
+    heading_6: {
+      title: "六級標題",
+      subtext: "用於小節和分組標題",
+      aliases: ["h6", "heading6", "subheading", "標題", "六級標題"],
+      group: "副標題",
+    },
     toggle_heading: {
       title: "可摺疊一級標題",
       subtext: "可摺疊的頂級標題",
       aliases: ["h", "heading1", "h1", "標題", "一級標題", "摺疊"],
-      group: "標題",
+      group: "副標題",
     },
     toggle_heading_2: {
       title: "可摺疊二級標題",
@@ -38,13 +56,13 @@ export const zhTW: Dictionary = {
         "副標題",
         "摺疊",
       ],
-      group: "標題",
+      group: "副標題",
     },
     toggle_heading_3: {
       title: "可摺疊三級標題",
       subtext: "可摺疊的小節和分組標題",
       aliases: ["h3", "heading3", "subheading", "標題", "三級標題", "摺疊"],
-      group: "標題",
+      group: "副標題",
     },
     quote: {
       title: "引用",
diff --git a/packages/core/src/i18n/locales/zh.ts b/packages/core/src/i18n/locales/zh.ts
index c0c25961d..1de7db42a 100644
--- a/packages/core/src/i18n/locales/zh.ts
+++ b/packages/core/src/i18n/locales/zh.ts
@@ -20,11 +20,29 @@ export const zh: Dictionary = {
       aliases: ["h3", "heading3", "subheading", "标题", "三级标题"],
       group: "标题",
     },
+    heading_4: {
+      title: "四级标题",
+      subtext: "用于较小的子节标题",
+      aliases: ["h4", "heading4", "subheading4", "四级标题"],
+      group: "副标题",
+    },
+    heading_5: {
+      title: "五级标题",
+      subtext: "用于较小的子节标题",
+      aliases: ["h5", "heading5", "subheading5", "五级标题"],
+      group: "副标题",
+    },
+    heading_6: {
+      title: "六级标题",
+      subtext: "用于最低层级的标题",
+      aliases: ["h6", "heading6", "subheading6", "六级标题"],
+      group: "副标题",
+    },
     toggle_heading: {
       title: "可折叠一级标题",
       subtext: "可折叠的顶级标题",
       aliases: ["h", "heading1", "h1", "标题", "一级标题", "折叠"],
-      group: "标题",
+      group: "副标题",
     },
     toggle_heading_2: {
       title: "可折叠二级标题",
@@ -38,13 +56,13 @@ export const zh: Dictionary = {
         "副标题",
         "折叠",
       ],
-      group: "标题",
+      group: "副标题",
     },
     toggle_heading_3: {
       title: "可折叠三级标题",
       subtext: "可折叠的小节和分组标题",
       aliases: ["h3", "heading3", "subheading", "标题", "三级标题", "折叠"],
-      group: "标题",
+      group: "副标题",
     },
     quote: {
       title: "引用",
diff --git a/packages/react/src/components/FormattingToolbar/DefaultSelects/BlockTypeSelect.tsx b/packages/react/src/components/FormattingToolbar/DefaultSelects/BlockTypeSelect.tsx
index eef2b1e7c..a2d61c7ea 100644
--- a/packages/react/src/components/FormattingToolbar/DefaultSelects/BlockTypeSelect.tsx
+++ b/packages/react/src/components/FormattingToolbar/DefaultSelects/BlockTypeSelect.tsx
@@ -11,6 +11,9 @@ import {
   RiH1,
   RiH2,
   RiH3,
+  RiH4,
+  RiH5,
+  RiH6,
   RiListCheck3,
   RiListOrdered,
   RiListUnordered,
@@ -77,6 +80,36 @@ export const blockTypeSelectItems = (
       "level" in block.props &&
       block.props.level === 3,
   },
+  {
+    name: dict.slash_menu.heading_4.title,
+    type: "heading",
+    props: { level: 4 },
+    icon: RiH4,
+    isSelected: (block) =>
+      block.type === "heading" &&
+      "level" in block.props &&
+      block.props.level === 4,
+  },
+  {
+    name: dict.slash_menu.heading_5.title,
+    type: "heading",
+    props: { level: 5 },
+    icon: RiH5,
+    isSelected: (block) =>
+      block.type === "heading" &&
+      "level" in block.props &&
+      block.props.level === 5,
+  },
+  {
+    name: dict.slash_menu.heading_6.title,
+    type: "heading",
+    props: { level: 6 },
+    icon: RiH6,
+    isSelected: (block) =>
+      block.type === "heading" &&
+      "level" in block.props &&
+      block.props.level === 6,
+  },
   {
     name: dict.slash_menu.toggle_heading.title,
     type: "heading",
diff --git a/packages/react/src/components/SuggestionMenu/getDefaultReactSlashMenuItems.tsx b/packages/react/src/components/SuggestionMenu/getDefaultReactSlashMenuItems.tsx
index 4e7c2cf55..62adf03b1 100644
--- a/packages/react/src/components/SuggestionMenu/getDefaultReactSlashMenuItems.tsx
+++ b/packages/react/src/components/SuggestionMenu/getDefaultReactSlashMenuItems.tsx
@@ -13,6 +13,9 @@ import {
   RiH1,
   RiH2,
   RiH3,
+  RiH4,
+  RiH5,
+  RiH6,
   RiImage2Fill,
   RiListCheck3,
   RiListOrdered,
@@ -31,6 +34,9 @@ const icons: Record<string, IconType> = {
   heading: RiH1,
   heading_2: RiH2,
   heading_3: RiH3,
+  heading_4: RiH4,
+  heading_5: RiH5,
+  heading_6: RiH6,
   toggle_heading: RiH1,
   toggle_heading_2: RiH2,
   toggle_heading_3: RiH3,
diff --git a/packages/xl-ai/src/api/schema/__snapshots__/schemaToJSONSchema.test.ts.snap b/packages/xl-ai/src/api/schema/__snapshots__/schemaToJSONSchema.test.ts.snap
index ec1c28279..c40733efa 100644
--- a/packages/xl-ai/src/api/schema/__snapshots__/schemaToJSONSchema.test.ts.snap
+++ b/packages/xl-ai/src/api/schema/__snapshots__/schemaToJSONSchema.test.ts.snap
@@ -50,6 +50,9 @@ exports[`creates json schema 1`] = `
                     1,
                     2,
                     3,
+                    4,
+                    5,
+                    6,
                   ],
                   "type": "number",
                 },
diff --git a/packages/xl-pdf-exporter/src/pdf/defaultSchema/blocks.tsx b/packages/xl-pdf-exporter/src/pdf/defaultSchema/blocks.tsx
index 1bc9d7082..79a2e1b07 100644
--- a/packages/xl-pdf-exporter/src/pdf/defaultSchema/blocks.tsx
+++ b/packages/xl-pdf-exporter/src/pdf/defaultSchema/blocks.tsx
@@ -67,12 +67,18 @@ export const pdfBlockMappingForDefaultSchema: BlockMapping<
     );
   },
   heading: (block, exporter) => {
-    const fontSizeEM =
-      block.props.level === 1 ? 2 : block.props.level === 2 ? 1.5 : 1.17;
+    const levelFontSizeEM = {
+      1: 2,
+      2: 1.5,
+      3: 1.17,
+      4: 1,
+      5: 0.83,
+      6: 0.67,
+    }[block.props.level];
     return (
       <Text
         style={{
-          fontSize: fontSizeEM * FONT_SIZE * PIXELS_PER_POINT,
+          fontSize: levelFontSizeEM * FONT_SIZE * PIXELS_PER_POINT,
           fontWeight: 700,
         }}
       >
diff --git a/tests/src/end-to-end/ariakit/ariakit.test.ts-snapshots/ariakit-emoji-picker-webkit-linux.png b/tests/src/end-to-end/ariakit/ariakit.test.ts-snapshots/ariakit-emoji-picker-webkit-linux.png
index 02baab8f2..3e48eae5e 100644
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diff --git a/tests/src/end-to-end/ariakit/ariakit.test.ts-snapshots/ariakit-link-toolbar-webkit-linux.png b/tests/src/end-to-end/ariakit/ariakit.test.ts-snapshots/ariakit-link-toolbar-webkit-linux.png
index 32c2b37c4..ce5e013ff 100644
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diff --git a/tests/src/end-to-end/ariakit/ariakit.test.ts-snapshots/ariakit-slash-menu-chromium-linux.png b/tests/src/end-to-end/ariakit/ariakit.test.ts-snapshots/ariakit-slash-menu-chromium-linux.png
index 9825ec51e..9dee39cb3 100644
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index 4a89300ce..9c7689e33 100644
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index 37caf33a1..139ec2032 100644
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diff --git a/tests/src/end-to-end/shadcn/shadcn.test.ts-snapshots/shadcn-formatting-toolbar-webkit-linux.png b/tests/src/end-to-end/shadcn/shadcn.test.ts-snapshots/shadcn-formatting-toolbar-webkit-linux.png
index 384b284f7..5b7116c94 100644
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diff --git a/tests/src/end-to-end/shadcn/shadcn.test.ts-snapshots/shadcn-image-toolbar-webkit-linux.png b/tests/src/end-to-end/shadcn/shadcn.test.ts-snapshots/shadcn-image-toolbar-webkit-linux.png
index 4f562f974..62005d1b9 100644
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diff --git a/tests/src/end-to-end/shadcn/shadcn.test.ts-snapshots/shadcn-link-toolbar-webkit-linux.png b/tests/src/end-to-end/shadcn/shadcn.test.ts-snapshots/shadcn-link-toolbar-webkit-linux.png
index 36395ce11..99964be6b 100644
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diff --git a/tests/src/end-to-end/shadcn/shadcn.test.ts-snapshots/shadcn-slash-menu-chromium-linux.png b/tests/src/end-to-end/shadcn/shadcn.test.ts-snapshots/shadcn-slash-menu-chromium-linux.png
index 8ba9721dd..49434267a 100644
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index ff4d4f83a..011d44ec6 100644
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index f283bd142..0f3eae697 100644
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diff --git a/tests/src/end-to-end/theming/theming.test.ts-snapshots/dark-formatting-toolbar-chromium-linux.png b/tests/src/end-to-end/theming/theming.test.ts-snapshots/dark-formatting-toolbar-chromium-linux.png
index 35b580119..303dc6358 100644
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diff --git a/tests/src/end-to-end/theming/theming.test.ts-snapshots/dark-slash-menu-chromium-linux.png b/tests/src/end-to-end/theming/theming.test.ts-snapshots/dark-slash-menu-chromium-linux.png
index ee03c98fc..15c37b5f6 100644
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diff --git a/tests/src/end-to-end/theming/theming.test.ts-snapshots/dark-slash-menu-firefox-linux.png b/tests/src/end-to-end/theming/theming.test.ts-snapshots/dark-slash-menu-firefox-linux.png
index 39e99f551..fa2b7c540 100644
Binary files a/tests/src/end-to-end/theming/theming.test.ts-snapshots/dark-slash-menu-firefox-linux.png and b/tests/src/end-to-end/theming/theming.test.ts-snapshots/dark-slash-menu-firefox-linux.png differ
diff --git a/tests/src/end-to-end/theming/theming.test.ts-snapshots/dark-slash-menu-webkit-linux.png b/tests/src/end-to-end/theming/theming.test.ts-snapshots/dark-slash-menu-webkit-linux.png
index a266ce2bf..c61094a7e 100644
Binary files a/tests/src/end-to-end/theming/theming.test.ts-snapshots/dark-slash-menu-webkit-linux.png and b/tests/src/end-to-end/theming/theming.test.ts-snapshots/dark-slash-menu-webkit-linux.png differ
diff --git a/tests/src/unit/core/createTestEditor.ts b/tests/src/unit/core/createTestEditor.ts
index ad11c2111..b7639f0a6 100644
--- a/tests/src/unit/core/createTestEditor.ts
+++ b/tests/src/unit/core/createTestEditor.ts
@@ -35,6 +35,9 @@ export const createTestEditor = <
           },
         },
       },
+      heading: {
+        levels: [1, 2, 3, 4, 5, 6],
+      },
       schema,
       trailingBlock: false,
       uploadFile: uploadToTmpFilesDotOrg_DEV_ONLY,
diff --git a/tests/src/unit/core/formatConversion/parse/__snapshots__/html/basicBlockTypes.json b/tests/src/unit/core/formatConversion/parse/__snapshots__/html/basicBlockTypes.json
index 477c02e9b..b8bc803a5 100644
--- a/tests/src/unit/core/formatConversion/parse/__snapshots__/html/basicBlockTypes.json
+++ b/tests/src/unit/core/formatConversion/parse/__snapshots__/html/basicBlockTypes.json
@@ -61,11 +61,68 @@
     "content": [
       {
         "styles": {},
-        "text": "Paragraph",
+        "text": "Heading 4",
         "type": "text",
       },
     ],
     "id": "4",
+    "props": {
+      "backgroundColor": "default",
+      "isToggleable": false,
+      "level": 4,
+      "textAlignment": "left",
+      "textColor": "default",
+    },
+    "type": "heading",
+  },
+  {
+    "children": [],
+    "content": [
+      {
+        "styles": {},
+        "text": "Heading 5",
+        "type": "text",
+      },
+    ],
+    "id": "5",
+    "props": {
+      "backgroundColor": "default",
+      "isToggleable": false,
+      "level": 5,
+      "textAlignment": "left",
+      "textColor": "default",
+    },
+    "type": "heading",
+  },
+  {
+    "children": [],
+    "content": [
+      {
+        "styles": {},
+        "text": "Heading 6",
+        "type": "text",
+      },
+    ],
+    "id": "6",
+    "props": {
+      "backgroundColor": "default",
+      "isToggleable": false,
+      "level": 6,
+      "textAlignment": "left",
+      "textColor": "default",
+    },
+    "type": "heading",
+  },
+  {
+    "children": [],
+    "content": [
+      {
+        "styles": {},
+        "text": "Paragraph",
+        "type": "text",
+      },
+    ],
+    "id": "7",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -76,7 +133,7 @@
   {
     "children": [],
     "content": undefined,
-    "id": "5",
+    "id": "8",
     "props": {
       "backgroundColor": "default",
       "caption": "Image Caption",
@@ -134,7 +191,7 @@
         "type": "text",
       },
     ],
-    "id": "6",
+    "id": "9",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
diff --git a/tests/src/unit/core/formatConversion/parse/__snapshots__/html/deepNestedContent.json b/tests/src/unit/core/formatConversion/parse/__snapshots__/html/deepNestedContent.json
index 9218e1545..420948fc2 100644
--- a/tests/src/unit/core/formatConversion/parse/__snapshots__/html/deepNestedContent.json
+++ b/tests/src/unit/core/formatConversion/parse/__snapshots__/html/deepNestedContent.json
@@ -129,11 +129,68 @@
     "content": [
       {
         "styles": {},
-        "text": "Paragraph",
+        "text": "Heading 4",
         "type": "text",
       },
     ],
     "id": "8",
+    "props": {
+      "backgroundColor": "default",
+      "isToggleable": false,
+      "level": 4,
+      "textAlignment": "left",
+      "textColor": "default",
+    },
+    "type": "heading",
+  },
+  {
+    "children": [],
+    "content": [
+      {
+        "styles": {},
+        "text": "Heading 5",
+        "type": "text",
+      },
+    ],
+    "id": "9",
+    "props": {
+      "backgroundColor": "default",
+      "isToggleable": false,
+      "level": 5,
+      "textAlignment": "left",
+      "textColor": "default",
+    },
+    "type": "heading",
+  },
+  {
+    "children": [],
+    "content": [
+      {
+        "styles": {},
+        "text": "Heading 6",
+        "type": "text",
+      },
+    ],
+    "id": "10",
+    "props": {
+      "backgroundColor": "default",
+      "isToggleable": false,
+      "level": 6,
+      "textAlignment": "left",
+      "textColor": "default",
+    },
+    "type": "heading",
+  },
+  {
+    "children": [],
+    "content": [
+      {
+        "styles": {},
+        "text": "Paragraph",
+        "type": "text",
+      },
+    ],
+    "id": "11",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -144,7 +201,7 @@
   {
     "children": [],
     "content": undefined,
-    "id": "9",
+    "id": "12",
     "props": {
       "backgroundColor": "default",
       "caption": "Image Caption",
@@ -217,7 +274,7 @@
         "type": "text",
       },
     ],
-    "id": "10",
+    "id": "13",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -234,7 +291,7 @@
         "type": "text",
       },
     ],
-    "id": "11",
+    "id": "14",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
diff --git a/tests/src/unit/core/formatConversion/parse/__snapshots__/html/googleDocs.json b/tests/src/unit/core/formatConversion/parse/__snapshots__/html/googleDocs.json
index 837e69abf..cb1c6802a 100644
--- a/tests/src/unit/core/formatConversion/parse/__snapshots__/html/googleDocs.json
+++ b/tests/src/unit/core/formatConversion/parse/__snapshots__/html/googleDocs.json
@@ -62,6 +62,69 @@
     },
     "type": "heading",
   },
+  {
+    "children": [],
+    "content": [
+      {
+        "styles": {
+          "bold": true,
+        },
+        "text": "Heading 4",
+        "type": "text",
+      },
+    ],
+    "id": "4",
+    "props": {
+      "backgroundColor": "default",
+      "isToggleable": false,
+      "level": 4,
+      "textAlignment": "left",
+      "textColor": "default",
+    },
+    "type": "heading",
+  },
+  {
+    "children": [],
+    "content": [
+      {
+        "styles": {
+          "bold": true,
+        },
+        "text": "Heading 5",
+        "type": "text",
+      },
+    ],
+    "id": "5",
+    "props": {
+      "backgroundColor": "default",
+      "isToggleable": false,
+      "level": 5,
+      "textAlignment": "left",
+      "textColor": "default",
+    },
+    "type": "heading",
+  },
+  {
+    "children": [],
+    "content": [
+      {
+        "styles": {
+          "bold": true,
+        },
+        "text": "Heading 6",
+        "type": "text",
+      },
+    ],
+    "id": "6",
+    "props": {
+      "backgroundColor": "default",
+      "isToggleable": false,
+      "level": 6,
+      "textAlignment": "left",
+      "textColor": "default",
+    },
+    "type": "heading",
+  },
   {
     "children": [],
     "content": [
@@ -71,7 +134,7 @@
         "type": "text",
       },
     ],
-    "id": "4",
+    "id": "7",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -88,7 +151,7 @@
         "type": "text",
       },
     ],
-    "id": "5",
+    "id": "8",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -105,7 +168,7 @@
         "type": "text",
       },
     ],
-    "id": "6",
+    "id": "9",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -123,7 +186,7 @@ Hard Break",
         "type": "text",
       },
     ],
-    "id": "7",
+    "id": "10",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -180,7 +243,7 @@ Hard Break",
         "type": "text",
       },
     ],
-    "id": "8",
+    "id": "11",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -201,7 +264,7 @@ Hard Break",
                 "type": "text",
               },
             ],
-            "id": "11",
+            "id": "14",
             "props": {
               "backgroundColor": "default",
               "textAlignment": "left",
@@ -218,7 +281,7 @@ Hard Break",
                 "type": "text",
               },
             ],
-            "id": "12",
+            "id": "15",
             "props": {
               "backgroundColor": "default",
               "textAlignment": "left",
@@ -234,7 +297,7 @@ Hard Break",
             "type": "text",
           },
         ],
-        "id": "10",
+        "id": "13",
         "props": {
           "backgroundColor": "default",
           "textAlignment": "left",
@@ -251,7 +314,7 @@ Hard Break",
             "type": "text",
           },
         ],
-        "id": "13",
+        "id": "16",
         "props": {
           "backgroundColor": "default",
           "textAlignment": "left",
@@ -267,7 +330,7 @@ Hard Break",
         "type": "text",
       },
     ],
-    "id": "9",
+    "id": "12",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -284,7 +347,7 @@ Hard Break",
         "type": "text",
       },
     ],
-    "id": "14",
+    "id": "17",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -301,7 +364,7 @@ Hard Break",
         "type": "text",
       },
     ],
-    "id": "15",
+    "id": "18",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -318,7 +381,7 @@ Hard Break",
         "type": "text",
       },
     ],
-    "id": "16",
+    "id": "19",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -329,7 +392,7 @@ Hard Break",
   {
     "children": [],
     "content": undefined,
-    "id": "17",
+    "id": "20",
     "props": {
       "backgroundColor": "default",
       "caption": "",
@@ -351,7 +414,7 @@ Hard Break",
         "type": "text",
       },
     ],
-    "id": "18",
+    "id": "21",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -538,7 +601,7 @@ Hard Break",
       ],
       "type": "tableContent",
     },
-    "id": "19",
+    "id": "22",
     "props": {
       "textColor": "default",
     },
@@ -553,7 +616,7 @@ Hard Break",
         "type": "text",
       },
     ],
-    "id": "20",
+    "id": "23",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -571,7 +634,7 @@ Hard Break",
         "type": "text",
       },
     ],
-    "id": "21",
+    "id": "24",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
diff --git a/tests/src/unit/core/formatConversion/parse/__snapshots__/html/notion.json b/tests/src/unit/core/formatConversion/parse/__snapshots__/html/notion.json
index 0c2eb8284..9b9d39ca3 100644
--- a/tests/src/unit/core/formatConversion/parse/__snapshots__/html/notion.json
+++ b/tests/src/unit/core/formatConversion/parse/__snapshots__/html/notion.json
@@ -61,11 +61,68 @@
     "content": [
       {
         "styles": {},
-        "text": "Paragraph 1",
+        "text": "Heading 4",
         "type": "text",
       },
     ],
     "id": "4",
+    "props": {
+      "backgroundColor": "default",
+      "isToggleable": false,
+      "level": 4,
+      "textAlignment": "left",
+      "textColor": "default",
+    },
+    "type": "heading",
+  },
+  {
+    "children": [],
+    "content": [
+      {
+        "styles": {},
+        "text": "Heading 5",
+        "type": "text",
+      },
+    ],
+    "id": "5",
+    "props": {
+      "backgroundColor": "default",
+      "isToggleable": false,
+      "level": 5,
+      "textAlignment": "left",
+      "textColor": "default",
+    },
+    "type": "heading",
+  },
+  {
+    "children": [],
+    "content": [
+      {
+        "styles": {},
+        "text": "Heading 6",
+        "type": "text",
+      },
+    ],
+    "id": "6",
+    "props": {
+      "backgroundColor": "default",
+      "isToggleable": false,
+      "level": 6,
+      "textAlignment": "left",
+      "textColor": "default",
+    },
+    "type": "heading",
+  },
+  {
+    "children": [],
+    "content": [
+      {
+        "styles": {},
+        "text": "Paragraph 1",
+        "type": "text",
+      },
+    ],
+    "id": "7",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -82,7 +139,7 @@
         "type": "text",
       },
     ],
-    "id": "5",
+    "id": "8",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -99,7 +156,7 @@
         "type": "text",
       },
     ],
-    "id": "6",
+    "id": "9",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -116,7 +173,7 @@
         "type": "text",
       },
     ],
-    "id": "7",
+    "id": "10",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -173,7 +230,7 @@
         "type": "text",
       },
     ],
-    "id": "8",
+    "id": "11",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -194,7 +251,7 @@
                 "type": "text",
               },
             ],
-            "id": "11",
+            "id": "14",
             "props": {
               "backgroundColor": "default",
               "textAlignment": "left",
@@ -211,7 +268,7 @@
                 "type": "text",
               },
             ],
-            "id": "12",
+            "id": "15",
             "props": {
               "backgroundColor": "default",
               "textAlignment": "left",
@@ -227,7 +284,7 @@
             "type": "text",
           },
         ],
-        "id": "10",
+        "id": "13",
         "props": {
           "backgroundColor": "default",
           "textAlignment": "left",
@@ -244,7 +301,7 @@
             "type": "text",
           },
         ],
-        "id": "13",
+        "id": "16",
         "props": {
           "backgroundColor": "default",
           "textAlignment": "left",
@@ -260,7 +317,7 @@
         "type": "text",
       },
     ],
-    "id": "9",
+    "id": "12",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -277,7 +334,7 @@
         "type": "text",
       },
     ],
-    "id": "14",
+    "id": "17",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -294,7 +351,7 @@
         "type": "text",
       },
     ],
-    "id": "15",
+    "id": "18",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -311,7 +368,7 @@
         "type": "text",
       },
     ],
-    "id": "16",
+    "id": "19",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -328,7 +385,7 @@
         "type": "text",
       },
     ],
-    "id": "17",
+    "id": "20",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -356,7 +413,7 @@
         "type": "link",
       },
     ],
-    "id": "18",
+    "id": "21",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -543,7 +600,7 @@
       ],
       "type": "tableContent",
     },
-    "id": "19",
+    "id": "22",
     "props": {
       "textColor": "default",
     },
@@ -558,7 +615,7 @@
         "type": "text",
       },
     ],
-    "id": "20",
+    "id": "23",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
diff --git a/tests/src/unit/core/formatConversion/parse/__snapshots__/markdown/complex.json b/tests/src/unit/core/formatConversion/parse/__snapshots__/markdown/complex.json
index e904a186d..758a0902a 100644
--- a/tests/src/unit/core/formatConversion/parse/__snapshots__/markdown/complex.json
+++ b/tests/src/unit/core/formatConversion/parse/__snapshots__/markdown/complex.json
@@ -61,11 +61,68 @@
     "content": [
       {
         "styles": {},
-        "text": "Paragraph",
+        "text": "Heading 4",
         "type": "text",
       },
     ],
     "id": "4",
+    "props": {
+      "backgroundColor": "default",
+      "isToggleable": false,
+      "level": 4,
+      "textAlignment": "left",
+      "textColor": "default",
+    },
+    "type": "heading",
+  },
+  {
+    "children": [],
+    "content": [
+      {
+        "styles": {},
+        "text": "Heading 5",
+        "type": "text",
+      },
+    ],
+    "id": "5",
+    "props": {
+      "backgroundColor": "default",
+      "isToggleable": false,
+      "level": 5,
+      "textAlignment": "left",
+      "textColor": "default",
+    },
+    "type": "heading",
+  },
+  {
+    "children": [],
+    "content": [
+      {
+        "styles": {},
+        "text": "Heading 6",
+        "type": "text",
+      },
+    ],
+    "id": "6",
+    "props": {
+      "backgroundColor": "default",
+      "isToggleable": false,
+      "level": 6,
+      "textAlignment": "left",
+      "textColor": "default",
+    },
+    "type": "heading",
+  },
+  {
+    "children": [],
+    "content": [
+      {
+        "styles": {},
+        "text": "Paragraph",
+        "type": "text",
+      },
+    ],
+    "id": "7",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -101,7 +158,7 @@
         "type": "text",
       },
     ],
-    "id": "5",
+    "id": "8",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -137,7 +194,7 @@
         "type": "text",
       },
     ],
-    "id": "6",
+    "id": "9",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -154,7 +211,7 @@
         "type": "text",
       },
     ],
-    "id": "7",
+    "id": "10",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -175,7 +232,7 @@
                 "type": "text",
               },
             ],
-            "id": "10",
+            "id": "13",
             "props": {
               "backgroundColor": "default",
               "textAlignment": "left",
@@ -191,7 +248,7 @@
             "type": "text",
           },
         ],
-        "id": "9",
+        "id": "12",
         "props": {
           "backgroundColor": "default",
           "textAlignment": "left",
@@ -210,7 +267,7 @@
                 "type": "text",
               },
             ],
-            "id": "12",
+            "id": "15",
             "props": {
               "backgroundColor": "default",
               "textAlignment": "left",
@@ -227,7 +284,7 @@
                 "type": "text",
               },
             ],
-            "id": "13",
+            "id": "16",
             "props": {
               "backgroundColor": "default",
               "textAlignment": "left",
@@ -246,7 +303,7 @@
                     "type": "text",
                   },
                 ],
-                "id": "15",
+                "id": "18",
                 "props": {
                   "backgroundColor": "default",
                   "textAlignment": "left",
@@ -262,7 +319,7 @@
                 "type": "text",
               },
             ],
-            "id": "14",
+            "id": "17",
             "props": {
               "backgroundColor": "default",
               "textAlignment": "left",
@@ -279,7 +336,7 @@
                 "type": "text",
               },
             ],
-            "id": "16",
+            "id": "19",
             "props": {
               "backgroundColor": "default",
               "textAlignment": "left",
@@ -295,7 +352,7 @@
             "type": "text",
           },
         ],
-        "id": "11",
+        "id": "14",
         "props": {
           "backgroundColor": "default",
           "textAlignment": "left",
@@ -312,7 +369,7 @@
             "type": "text",
           },
         ],
-        "id": "17",
+        "id": "20",
         "props": {
           "backgroundColor": "default",
           "textAlignment": "left",
@@ -328,7 +385,7 @@
         "type": "text",
       },
     ],
-    "id": "8",
+    "id": "11",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
@@ -345,7 +402,7 @@
         "type": "text",
       },
     ],
-    "id": "18",
+    "id": "21",
     "props": {
       "backgroundColor": "default",
       "textAlignment": "left",
diff --git a/tests/src/unit/core/formatConversion/parse/parseTestInstances.ts b/tests/src/unit/core/formatConversion/parse/parseTestInstances.ts
index db65f162f..24691a394 100644
--- a/tests/src/unit/core/formatConversion/parse/parseTestInstances.ts
+++ b/tests/src/unit/core/formatConversion/parse/parseTestInstances.ts
@@ -22,6 +22,9 @@ export const parseTestInstancesHTML: TestInstance<
       content: `<h1>Heading 1</h1>
 <h2>Heading 2</h2>
 <h3>Heading 3</h3>
+<h4>Heading 4</h4>
+<h5>Heading 5</h5>
+<h6>Heading 6</h6>
 <p>Paragraph</p>
 <figure><img src="exampleURL" /><figcaption>Image Caption</figcaption></figure>
 <p>None <strong>Bold </strong><em>Italic </em><u>Underline </u><s>Strikethrough </s><strong><em><s><u>All</u></s></em></strong></p>`,
@@ -576,6 +579,9 @@ export const parseTestInstancesHTML: TestInstance<
         <h1>Heading 1</h1>
         <h2>Heading 2</h2>
         <h3>Heading 3</h3>
+        <h4>Heading 4</h4>
+        <h5>Heading 5</h5>
+        <h6>Heading 6</h6>
         <p>Paragraph</p>
         <figure><img src="exampleURL"><figcaption>Image Caption</figcaption></figure>
         <p><strong>Bold</strong> <em>Italic</em> <u>Underline</u> <s>Strikethrough</s> <strong><em><s><u>All</u></s></em></strong></p>
@@ -642,6 +648,9 @@ export const parseTestInstancesHTML: TestInstance<
       content: `<meta charset='utf-8'><h1>Heading 1</h1>
 <h2>Heading 2</h2>
 <h3>Heading 3</h3>
+<h4>Heading 4</h4>
+<h5>Heading 5</h5>
+<h6>Heading 6</h6>
 <p>Paragraph 1</p>
 <p>Nested Paragraph 1</p>
 <p>Nested Paragraph 2</p>
@@ -703,6 +712,9 @@ With Hard Break</p>
 <h1 dir="ltr" style="line-height:1.38;margin-left: 18pt;text-indent: -18pt;margin-top:24pt;margin-bottom:6pt;padding:0pt 0pt 0pt 18pt;"><span style="font-size:23pt;font-family:Arial,sans-serif;color:#000000;background-color:transparent;font-weight:700;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline;white-space:pre;white-space:pre-wrap;">Heading 1</span></h1>
 <h2 dir="ltr" style="line-height:1.38;margin-left: 18pt;text-indent: -18pt;margin-top:18pt;margin-bottom:4pt;padding:0pt 0pt 0pt 18pt;"><span style="font-size:17pt;font-family:Arial,sans-serif;color:#000000;background-color:transparent;font-weight:700;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline;white-space:pre;white-space:pre-wrap;">Heading 2</span></h2>
 <h3 dir="ltr" style="line-height:1.38;margin-left: 18pt;text-indent: -18pt;margin-top:14pt;margin-bottom:4pt;padding:0pt 0pt 0pt 18pt;"><span style="font-size:13pt;font-family:Arial,sans-serif;color:#000000;background-color:transparent;font-weight:700;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline;white-space:pre;white-space:pre-wrap;">Heading 3</span></h3>
+<h4 dir="ltr" style="line-height:1.38;margin-left: 18pt;text-indent: -18pt;margin-top:14pt;margin-bottom:4pt;padding:0pt 0pt 0pt 18pt;"><span style="font-size:13pt;font-family:Arial,sans-serif;color:#000000;background-color:transparent;font-weight:700;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline;white-space:pre;white-space:pre-wrap;">Heading 4</span></h4>
+<h5 dir="ltr" style="line-height:1.38;margin-left: 18pt;text-indent: -18pt;margin-top:14pt;margin-bottom:4pt;padding:0pt 0pt 0pt 18pt;"><span style="font-size:13pt;font-family:Arial,sans-serif;color:#000000;background-color:transparent;font-weight:700;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline;white-space:pre;white-space:pre-wrap;">Heading 5</span></h5>
+<h6 dir="ltr" style="line-height:1.38;margin-left: 18pt;text-indent: -18pt;margin-top:14pt;margin-bottom:4pt;padding:0pt 0pt 0pt 18pt;"><span style="font-size:13pt;font-family:Arial,sans-serif;color:#000000;background-color:transparent;font-weight:700;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline;white-space:pre;white-space:pre-wrap;">Heading 6</span></h6>
 <p dir="ltr" style="line-height:1.38;margin-top:12pt;margin-bottom:12pt;"><span style="font-size:11pt;font-family:Arial,sans-serif;color:#000000;background-color:transparent;font-weight:400;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline;white-space:pre;white-space:pre-wrap;">Paragraph 1</span></p>
 <p dir="ltr" style="line-height:1.38;margin-top:12pt;margin-bottom:12pt;"><span style="font-size:11pt;font-family:Arial,sans-serif;color:#000000;background-color:transparent;font-weight:400;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline;white-space:pre;white-space:pre-wrap;">Paragraph 2</span></p>
 <p dir="ltr" style="line-height:1.38;margin-top:12pt;margin-bottom:12pt;"><span style="font-size:11pt;font-family:Arial,sans-serif;color:#000000;background-color:transparent;font-weight:400;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline;white-space:pre;white-space:pre-wrap;">Paragraph 3</span></p>
@@ -854,6 +866,12 @@ Paragraph
 
 ### Heading 3
 
+#### Heading 4
+
+##### Heading 5
+
+###### Heading 6
+
 Paragraph
 
 P**ara***grap*h