diff --git a/src/wp-includes/block-editor.php b/src/wp-includes/block-editor.php
index c872ae84fd..11df4c9a10 100644
--- a/src/wp-includes/block-editor.php
+++ b/src/wp-includes/block-editor.php
@@ -309,10 +309,13 @@ function _wp_get_iframed_editor_assets() {
 	$style_handles  = array(
 		'wp-block-editor',
 		'wp-block-library',
-		'wp-block-library-theme',
 		'wp-edit-blocks',
 	);
 
+	if ( current_theme_supports( 'wp-block-styles' ) ) {
+		$style_handles[] = 'wp-block-library-theme';
+	}
+
 	if ( 'widgets.php' === $pagenow || 'customize.php' === $pagenow ) {
 		$style_handles[] = 'wp-widgets';
 		$style_handles[] = 'wp-edit-widgets';