Europarties—multinational alliances uniting political parties aligned by ideology on the European level—are often viewed as creatures of their members with little to no endogenous agency. This chapter examines this perspective from the prism of membership admission in the context of the EU election campaign 2024. The central research question is: “Who are the actors in the admission process of new Europarty members, and what is their role?” Party statutes and semi-structured interviews with current and former Europarty staff and political personnel from the 2024 EU election campaign reveal that the headquarters play an essential yet informal role in the membership admission process. As such, they shape the membership, which controls decision-making within the Europarty. The chapter concludes that while European political parties remain “parties of parties”, they are creatures of their membership as much as the membership is a creature of the European political party headquarters.