Using data from the Online College Social Life Survey, we examine the contexts in which there is a gender gap in regretting hookups, as well as the mechanisms that explain these gender gaps. Results suggest that gender differences in regret are larger following (and in the case of most recent hookups, limited to) hookups that involve vaginal intercourse. The gender gap in hookup regret is mostly a function of gender differences in sexual initiation, sexual agency, sexual enjoyment, loss of respect from one’s partner, and loss of self-respect. These findings suggest that the gendered norms and power imbalance created by the sexual double standard explain why women regret hookups involving vaginal intercourse more often than men do.