This study explores multiple coalition memberships in multilateral negotiations, with a focus on climate negotiations. Why do countries engage in multiple coalitions, and how do multiple coalition memberships affect their influence? I argue that coalitions differ in important respects. Accordingly, countries may belong to both, long-term and short-lived coalitions; they may consciously decide to join a coalition, but also be associated by default. Finally, larger coalitions confer numerical strength, while smaller (sub-)coalitions help voice common positions. Regarding effects, I propose two perspectives. The zero-sum perspective highlights coordination costs and potentially incompatible positions, while the win-win perspective focuses on the complementarity of different coalitions and the potential for mutual support. Anecdotal evidence from the climate negotiations offers support for these perspectives, but further empirical research is needed to better understand why countries join several coalitions, how they navigate these multiple coalition memberships, and how these affect their influence.