diff --git a/include/ruby/internal/intern/hash.h b/include/ruby/internal/intern/hash.h
index c7a27c2cfa..70c37917f1 100644
--- a/include/ruby/internal/intern/hash.h
+++ b/include/ruby/internal/intern/hash.h
@@ -52,7 +52,6 @@ int rb_path_check(const char*);
 int rb_env_path_tainted(void);
 VALUE rb_env_clear(void);
 VALUE rb_hash_size(VALUE);
-void rb_hash_free(VALUE);
 
 RBIMPL_SYMBOL_EXPORT_END()