diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index 08d85695..f689c58b 100644
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -531,7 +531,7 @@ Gosu:
 
 Grammatical Framework:
   type: programming
-  lexer: haskell
+  lexer: Haskell
   aliases:
   - gf
   wrap: false