diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index 6eb2a378..8bec1704 100644
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -230,6 +230,8 @@ C:
   extensions:
   - .cats
   - .w
+  - .C
+  - .H
 
 C#:
   type: programming