Criminal organizations kill tens of thousands each year. This article argues that criminal organizations under women leadership are less violent due to women's gendered pathways to power. We examine Mexico’s Tijuana Cartel and leverage the 2008 ascension of a woman to leadership following her brother's arrest. Synthetic control results show that the Tijuana Cartel reduced visible violence and territorial expansion under a woman's leadership, but slightly increased hidden forms of violence. Original data on all male cartel leaders in Mexico shows systematic gender differences in pre-leadership violent socialization and expertise that help explain the results. We probe generalizability by constructing 44 case studies of women criminal leaders across 18 countries since 1850 and find that gender profoundly shapes their trajectories, with our findings likely extending to women who inherit leadership from male kin. Our findings highlight the need to incorporate gender into research on organized crime.

Criminal organizations (COs) often fragment, triggering inter-CO wars that are frequently deadlier than civil wars. Despite fragmentation being a major driver of violence, we know little about who fragments, when, or how. This article theorizes that potential defectors, differing in strength relative to their parent CO, strategically weigh two concerns when considering fragmenting during moments of organizational uncertainty: economic viability that depends on illicit market structure and surviving retaliation that is conditioned by geography and alliances. Leveraging an original dataset of Mexico's drug cartels and their fragments from 2000 to 2018, we find that fragmentation is rare even after leadership decapitation, and that strong fragments can operate near their parent cartel, compete in similar markets, and form military alliances with other cartels to withstand retaliation, while weaker fragments survive by operating in distant areas and more localized markets. These findings provide the microfoundations for criminal fragmentation as a strategic process.