@@ -0,0 +1,43 @@
+/**
+ * Transforms paragraphs with heading semantics into proper heading tags.
+ *
+ * This handles cases where content (like from Microsoft Word Online) comes in as
+ * <p> tags with role="heading" and aria-level attributes, and converts them to
+ * proper <h1>, <h2>, etc. tags.
+ *
+ * @param {Node} node The node to check and potentially transform.
+ */
+export default function headingTransformer( node ) {
+	if ( node.nodeType !== node.ELEMENT_NODE ) {
+		return;
+	}
+
+	// Check if this is a paragraph with heading semantics.
+	if (
+		node.tagName === 'P' &&
+		node.getAttribute( 'role' ) === 'heading' &&
+		node.hasAttribute( 'aria-level' )
+	) {
+		const level = parseInt( node.getAttribute( 'aria-level' ), 10 );
+
+		// To ensure valid heading level (1-6).
+		if ( level >= 1 && level <= 6 ) {
+			const headingTag = `H${ level }`;
+			const newHeading = node.ownerDocument.createElement( headingTag );
+
+			// Copying all attributes except role and aria-level.
+			Array.from( node.attributes ).forEach( ( attr ) => {
+				if ( attr.name !== 'role' && attr.name !== 'aria-level' ) {
+					newHeading.setAttribute( attr.name, attr.value );
+				}
+			} );
+
+			while ( node.firstChild ) {
+				newHeading.appendChild( node.firstChild );
+			}
+
+			// Replacing the paragraph with the heading.
+			node.parentNode.replaceChild( newHeading, node );
+		}
+	}
+}
@@ -34,6 +34,7 @@ import emptyParagraphRemover from './empty-paragraph-remover';
 import slackParagraphCorrector from './slack-paragraph-corrector';
 import isLatexMathMode from './latex-to-math';
 import { createBlock } from '../factory';
+import headingTransformer from './heading-transformer';
 
 const log = ( ...args ) => window?.console?.log?.( ...args );
 
@@ -204,6 +205,7 @@ export function pasteHandler( {
 				figureContentReducer,
 				blockquoteNormaliser(),
 				divNormaliser,
+				headingTransformer,
 			];
 
 			const schema = {
 
@@ -9,19 +9,18 @@ This folder contains all paste specific logic (filters, converters, normalisers.
 | Google Docs      | ✓          | ✓        | ✓     | ✓     | ✓         | ✓     | ✘ [1]               |
 | Apple Pages      | ✓          | ✘ [2]    | ✓     | ✘ [2] | n/a       | ✓     | ✘ [1]               |
 | MS Word          | ✓          | ✓        | ✓     | ✓     | n/a       | ✓     | ✓                   |
-| MS Word Online   | ✓          | ✘ [4]    | ✓     | ✓     | n/a       | ✓     | ✘ [1]               |
+| MS Word Online   | ✓          | ✓        | ✓     | ✓     | n/a       | ✓     | ✘ [1]               |
 | LibreOffice      | ✓          | ✓        | ✓     | ✘ [3] | ✓         | ✓     | ✓                   |
-| Evernote         | ✓          | ✘ [5]    | ✓     | ✓     | ✓         | ✓     | n/a                 |
+| Evernote         | ✓          | ✘ [4]    | ✓     | ✓     | ✓         | ✓     | n/a                 |
 | Markdown         | ✓          | ✓        | ✓     | ✓     | ✓         | ✓     | n/a                 |
-| Legacy WordPress | ✓          | ✓        | ✓     | … [6] | ✓         | ✓     | n/a                 |
+| Legacy WordPress | ✓          | ✓        | ✓     | … [5] | ✓         | ✓     | n/a                 |
 | Web              | ✓          | ✓        | ✓     | ✓     | ✓         | ✓     | n/a                 |
 
 1. Google Docs, Apple Pages and MS Word online don't pass footnote nor endnote information.
 2. Apple Pages does not pass heading and image information.
 3. LibreOffice only provide a local file path, which cannot be accessed in JavaScript for security reasons. Image placeholders will be provided instead. Single images, however, _can_ be copied and pasted without any problem.
-4. Still to do for MS Word Online.
-5. Evernote does not have headings.
-6. For caption and gallery shortcodes, see #2874.
+4. Evernote does not have headings.
+5. For caption and gallery shortcodes, see #2874.
 
 ## Other notable capabilities
 
 
@@ -1,6 +1,6 @@
-<!-- wp:paragraph -->
-<p>This is a <em>heading</em>&nbsp;</p>
-<!-- /wp:paragraph -->
+<!-- wp:heading {"level":1} -->
+<h1 class="wp-block-heading">This is a <em>heading</em>&nbsp;</h1>
+<!-- /wp:heading -->
 
 <!-- wp:paragraph -->
 <p>This is a <strong>paragraph </strong>with a <a href="https://w.org/" target="_blank" rel="noreferrer noopener">link</a>.&nbsp;</p>