Despite gains at lower levels, women have made limited inroads into leadership roles in international organizations. Using a novel data set of both nominees and selected heads of 129 international organizations, we uncover several empirical patterns. Women’s representation at the highest levels remains far below parity but has been improving steadily since the 1990s. One caveat is that this improvement has only occurred in a subset of institutions, which suggests a concentration of women leaders. Based on the available data, we examine whether the appointment of a woman leader impacts equality in the institution’s overall staffing profile. We find that such changes occur only once there is a history of appointing women. We also look at the nominations process and find that when women are included in the nominee pool, they tend to be selected, although often they are absent. Our analysis contributes much-needed data to the broader literature on leadership in international organizations and introduces a new data set with a range of other potential applications.