diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index 46bbd766..87025cde 100644
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -423,6 +423,7 @@ JavaScript:
   - node
   extensions:
   - .js
+  - .jsm
   - .sjs
   - .jss
   - .ssjs