diff --git a/cc/builder.go b/cc/builder.go
index f795bba..730c9ca 100644
--- a/cc/builder.go
+++ b/cc/builder.go
@@ -250,7 +250,7 @@
 		case ".c":
 			ccCmd = "gcc"
 			moduleCflags = cflags
-		case ".cpp", ".cc":
+		case ".cpp", ".cc", ".mm":
 			ccCmd = "g++"
 			moduleCflags = cppflags
 		default: