Previous research has suggested that homosexual men are less aggressive than heterosexual men, but limitations of available studies prevent them from being conclusive. The empirical evidence is even more mixed regarding the relation of aggressiveness to female sexual orientation. We examined the relation between self-reported physical and verbal aggressiveness, interpersonal competitiveness, and sexual orientation in both men and women. The aggressiveness and competitiveness scales yielded significant sex differences, with men being more aggressive and competitive. Consistent with past findings, heterosexual men were more physically aggressive than were homosexual men; no other within-sex relationship was significant. We discuss the implications of our findings for developmental theories of sexual orientation, aggressiveness, and competitiveness.