This chapter elucidates the most important value inherent to enhanced cooperation: the value of tolerance. The notion of tolerance is not a one-way street: Member States within enhanced cooperation have to respect fellow Member States outside enhanced cooperation, as well as their wish to pursue the European objectives on a unilateral path. Likewise, Member States outside enhanced cooperation have to respect that some Member States will pursue a legislative act jointly. The chapter clearly shows that the principle of tolerance is different from the principle of sincere cooperation, since the protection of Art 327 of the TFEU demands more than a loyal interaction between Member States. International law and constitutional law provisions on cooperation in federal states provide guidance on how to develop a framework for the principle of tolerance within enhanced cooperation.