Extant research examining the effects of top management team (TMT) gender diversity on firm performance report equivocal findings. We seek to enhance understanding of this critical relationship in the context of an acquisition, which necessitates changes in one or both firms during a process characterized by non-routine decisions, time pressures, high uncertainty, and frequent debates among strategic leaders. Specifically, we examine the effects of gender diversity of top management and female executives’ formal and informal power on post-deal performance. Our results indicate gender diversity has negative effects on post-deal performance. Further, in a subsample of acquirers with gender diverse teams, our results reveal that female executives’ structural power and ownership power have negative performance effects, while power conferred through an elite education has positive performance effects. Our findings highlight the need to expand gender diversity research to consider the strategic context facing diverse TMTs and power dynamics among them.