It may not be so obvious how respond_to? works in ruby. Consider that: class A def public_method end protected def protected_method end private def private_method end end obj = A.new obj.respond_to?(:public_method) # true - that's pretty obvious obj.respond_to?(:private_method) # false - as expected obj.respond_to?(:protected_method) # true - WTF? So if 'obj' responds to protected_method we should expect obj.protected_method not to raise an exception, shouldn't we? ...but it raises obviously Documentation points that calling respond_to? with 2nd argument set to true check private method as well obj.respond_to?(:private_method, true) # true And that's far more reasonable So the question is how to check if object responds to public method only? Is there a solution better than that? obj.methods.include?(:public_method) # true obj.methods.include?(:protected_method) # false