diff --git a/src/wp-includes/functions.php b/src/wp-includes/functions.php
index 6ddd11f071..fb17eda82b 100644
--- a/src/wp-includes/functions.php
+++ b/src/wp-includes/functions.php
@@ -3454,7 +3454,7 @@ function wp_get_mime_types() {
 			'mp3|m4a|m4b'                  => 'audio/mpeg',
 			'aac'                          => 'audio/aac',
 			'ra|ram'                       => 'audio/x-realaudio',
-			'wav'                          => 'audio/wav',
+			'wav|x-wav'                    => 'audio/wav',
 			'ogg|oga'                      => 'audio/ogg',
 			'flac'                         => 'audio/flac',
 			'mid|midi'                     => 'audio/midi',