diff --git a/kernel.rb b/kernel.rb
index 442fb4a0b6..f8ca908fa0 100644
--- a/kernel.rb
+++ b/kernel.rb
@@ -293,7 +293,7 @@ module Kernel
 
   # Internal helper for built-in initializations to define methods only when YJIT is enabled.
   # This method is removed in yjit_hook.rb.
-  def with_yjit(&block) # :nodoc:
+  private def with_yjit(&block) # :nodoc:
     if defined?(RubyVM::YJIT)
       RubyVM::YJIT.send(:add_yjit_hook, block)
     end