diff --git a/internal.h b/internal.h
index e32bf82260..b66db45aba 100644
--- a/internal.h
+++ b/internal.h
@@ -30,7 +30,7 @@
 
 #include "ruby/ruby.h"
 
-/* Folowing macros were formerlly defined in this header but moved to somewhere
+/* Following macros were formerly defined in this header but moved to somewhere
  * else.  In order to detect them we undef here. */
 
 /* internal/error.h */