Well, it just turned out that you were wrong. There's nothing special about INIT or BEGIN when it comes to inheritance. Inheritance just requires that @ISA have been set at some time prior to when an @ISA-using operation is executing. It's an utter red herring. If a person is stuck with making the change occur "earlier" they can always say BEGIN { @ISA = ... } or use base ...; both of which push that bit of @ISA setting as early as possible for that little snippet of code.