diff --git a/blocks/api/serializer.js b/blocks/api/serializer.js
index 66b7421979064..55340ae29729b 100644
--- a/blocks/api/serializer.js
+++ b/blocks/api/serializer.js
@@ -115,6 +115,10 @@ export function serializeBlock( block ) {
 	const saveContent = getSaveContent( blockType, block.attributes );
 	const saveAttributes = getCommentAttributes( block.attributes, parseBlockAttributes( saveContent, blockType ) );
 
+	if ( 'wp:core/more' === blockName ) {
+		return `<!-- more ${ saveAttributes.customText ? `${ saveAttributes.customText } ` : '' }-->${ saveAttributes.noTeaser ? '\n<!--noteaser-->' : '' }`;
+	}
+
 	const serializedAttributes = ! isEmpty( saveAttributes )
 		? serializeAttributes( saveAttributes ) + ' '
 		: '';