This Article analyzes the way federal courts conduct their superiority inquiries on motions for class certification in transnational class actions. Opt-out class actions under Rule 23(b)(3) conflict with an important premise of legal systems around the world, namely, that one cannot be bound to a judgment unless one affirmatively participated in the lawsuit. Federal courts sometimes either decline to certify the class or exclude foreign class members from the class because of the risk that the courts of foreign countries will not enforce the class action judgment. This Article argues that the current approach inefficiently exposes the parties to costly litigation and risk. In order to efficiently achieve the purposes of Rule 23, courts shou...