diff --git a/packages/block-library/src/comments/index.php b/packages/block-library/src/comments/index.php
index 48aac15af6fbb6..fbcff6217c0e33 100644
--- a/packages/block-library/src/comments/index.php
+++ b/packages/block-library/src/comments/index.php
@@ -76,6 +76,7 @@ function render_block_core_comments( $attributes, $content, $block ) {
 	 * why they are not defined in `block.json`.
 	 */
 	wp_enqueue_script( 'comment-reply' );
+	wp_script_add_data( 'comment-reply', 'strategy', 'defer' );
 	enqueue_legacy_post_comments_block_styles( $block->name );
 
 	return sprintf( '<div %1$s>%2$s</div>', $wrapper_attributes, $output );
diff --git a/packages/block-library/src/post-comments-form/index.php b/packages/block-library/src/post-comments-form/index.php
index 644b02ae0f1498..4f4f7b6ee87748 100644
--- a/packages/block-library/src/post-comments-form/index.php
+++ b/packages/block-library/src/post-comments-form/index.php
@@ -48,6 +48,7 @@ function render_block_core_post_comments_form( $attributes, $content, $block ) {
 
 	// Enqueue the comment-reply script.
 	wp_enqueue_script( 'comment-reply' );
+	wp_script_add_data( 'comment-reply', 'strategy', 'defer' );
 
 	return $form;
 }