diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index c61ebd72..ca90cbc9 100644
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -1218,6 +1218,8 @@ Standard ML:
   aliases:
   - sml
   primary_extension: .sml
+  extensions:
+  - .fun
 
 SuperCollider:
   type: programming