Mass shooters, violent extremists, and terrorists, who are overwhelmingly male, exhibit misogynistic attitudes and a history of violence against women. Over the past few years, incels ("involuntary celibates") have gathered in online communities to discuss their frustration with sexual/romantic rejection, espouse male supremacist attitudes, and justify violence against women and men who are more popular with women. Despite the link between misogyny and mass violence, and the recent emergence of online misogynistic extremism, theories and empirical research on misogynistic extremism remain scarce. I posit that the unique interaction between evolved male psychology, the dynamics of the sexual marketplace, and modern technologies create an ecology in which incel beliefs can thrive and make violence attractive. I show how individual factors, particularly low status, and social forces, such as a high degree of status inequality, female empowerment, and the ease of coordination through social media, give rise to misogynistic extremism.