diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index c2d31220..9816ad36 100644
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -1106,6 +1106,7 @@ OCaml:
   primary_extension: .ml
   extensions:
   - .eliomi
+  - .ml4
   - .mli
   - .mll
   - .mly