How do we account for the dearth of female contributions to UN peace operations (UNPOs)? For answers, this study examines conditions that led the United Nations to move to reduce the gender imbalance in UNPO personnel and provides descriptive evidence that points to the continuing underrepresentation of women in these operations. To interpret this evidence, the study presents theoretical explanations for the varying contributions of personnel to UNPOs—including the political and socioeconomic character of the contributing states, international reputations and norms, and various demand-side influences exerted by missions—and then tests these explanations with a cross-sectional time-series model that accounts for female personnel contributions to each mission in the 2010–2011 period. Although offering significant support for domestic political explanations, the findings indicate that gender diversity is not a primary goal of most contributors and is largely a by-product of force sizes.