diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index c269bf93..28c9a5a4 100644
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -1593,7 +1593,7 @@ Lean:
   extensions:
   - .lean
   - .hlean
-  ace_mode: text
+  ace_mode: lean
 
 Less:
   type: markup