Why do some cultures go extinct while others prevail? We show that a society’s risk of cultural extinction, proxied by language loss, is shaped by its ancestral gender norms and by how these differ from those of competing cultures. Using the Ethnologue and the Male Dominance Index for a global sample of languages, we first show that languages from more gender-equal societies are likelier to go extinct. In our framework, male-dominant societies are more expansionist through two channels, military capacity sustained by surplus extraction and demographic pressure from women's specialization in domestic and reproductive labor, and therefore expand at the expense of gender-egalitarian groups. We test this in two settings. Under European colonization, we find that Indigenous groups more gender-equal than their colonizers are more vulnerable to extinction, which is best explained by asymmetries in male dominance rather than dominance more broadly. Exploiting local variation in neighbors' gender structure across Africa, we show that languages from more gender-egalitarian societies are less likely to survive in cells located close to male-dominant neighbors, with military capacity and population pressure predicting language expansion.