diff --git a/src/wp-includes/script-loader.php b/src/wp-includes/script-loader.php
index a364439f0abbb..6b87367be522a 100644
--- a/src/wp-includes/script-loader.php
+++ b/src/wp-includes/script-loader.php
@@ -4,7 +4,7 @@
  *
  * Several constants are used to manage the loading, concatenating and compression of scripts and CSS:
  * define('SCRIPT_DEBUG', true); loads the development (non-minified) versions of all scripts and CSS, and disables compression and concatenation,
- * define('CONCATENATE_SCRIPTS', false); disables compression and concatenation of scripts and CSS,
+ * define('CONCATENATE_SCRIPTS', true); enables concatenation of scripts and CSS in the admin and on the login screen (disabled by default),
  * define('COMPRESS_SCRIPTS', false); disables compression of scripts,
  * define('COMPRESS_CSS', false); disables compression of CSS,
  * define('ENFORCE_GZIP', true); forces gzip for compression (default is deflate).
@@ -2476,7 +2476,7 @@ function script_concat_settings() {
 	$can_compress_scripts = ! wp_installing() && get_site_option( 'can_compress_scripts' );
 
 	if ( ! isset( $concatenate_scripts ) ) {
-		$concatenate_scripts = defined( 'CONCATENATE_SCRIPTS' ) ? CONCATENATE_SCRIPTS : true;
+		$concatenate_scripts = defined( 'CONCATENATE_SCRIPTS' ) ? CONCATENATE_SCRIPTS : false;
 		if ( ( ! is_admin() && ! did_action( 'login_init' ) ) || ( defined( 'SCRIPT_DEBUG' ) && SCRIPT_DEBUG ) ) {
 			$concatenate_scripts = false;
 		}