diff --git a/Lib/mimetypes.py b/Lib/mimetypes.py
index 4b1e2f945a9..8ce02f9200b 100644
--- a/Lib/mimetypes.py
+++ b/Lib/mimetypes.py
@@ -430,7 +430,7 @@ def _default_mime_types():
         '.jpe'    : 'image/jpeg',
         '.jpeg'   : 'image/jpeg',
         '.jpg'    : 'image/jpeg',
-        '.js'     : 'application/x-javascript',
+        '.js'     : 'application/javascript',
         '.ksh'    : 'text/plain',
         '.latex'  : 'application/x-latex',
         '.m1v'    : 'video/mpeg',
diff --git a/Misc/ACKS b/Misc/ACKS
index 0d851df3134..30505cd0058 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -480,6 +480,7 @@ Jens B. Jorgensen
 Sijin Joseph
 Andreas Jung
 Tattoo Mabonzo K.
+Bohuslav Kabrda
 Bob Kahn
 Kurt B. Kaiser
 Tamito Kajiyama
diff --git a/Misc/NEWS b/Misc/NEWS
index 74c168f1c53..a8b560e8803 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -107,6 +107,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #15199: Fix JavaScript's default MIME type to application/javascript.
+  Patch by Bohuslav Kabrda.
+
 - Issue #13579: string.Formatter now understands the 'a' conversion specifier.
 
 - Issue #15595: Fix subprocess.Popen(universal_newlines=True)