diff --git a/src/wp-includes/block-editor.php b/src/wp-includes/block-editor.php
index c177d9619d..1c67e6cc7a 100644
--- a/src/wp-includes/block-editor.php
+++ b/src/wp-includes/block-editor.php
@@ -192,12 +192,17 @@ function get_default_block_editor_settings() {
 	// These styles are used if the "no theme styles" options is triggered or on
 	// themes without their own editor styles.
 	$default_editor_styles_file = ABSPATH . WPINC . '/css/dist/block-editor/default-editor-styles.css';
-	if ( file_exists( $default_editor_styles_file ) ) {
+
+	static $default_editor_styles_file_contents = false;
+	if ( ! $default_editor_styles_file_contents && file_exists( $default_editor_styles_file ) ) {
+		$default_editor_styles_file_contents = file_get_contents( $default_editor_styles_file );
+	}
+
+	$default_editor_styles = array();
+	if ( $default_editor_styles_file_contents ) {
 		$default_editor_styles = array(
-			array( 'css' => file_get_contents( $default_editor_styles_file ) ),
+			array( 'css' => $default_editor_styles_file_contents ),
 		);
-	} else {
-		$default_editor_styles = array();
 	}
 
 	$editor_settings = array(