Little is known about the beliefs men and women have about the causes of sexual desire, despite the interpersonal and individual significance of those beliefs. Participants in this study received a definition of sexual desire and answered a set of free-response questions exploring their beliefs about the causal antecedents of male and female sexual desire. The results indicated that more women than men view female (and male) sexual desire as caused by external factors. In addition, both men and women believe that male and female sexual desire have different causes: intraindividual and erotic environmental factors are believed to cause male sexual desire, but interpersonal and romantic environmental factors are believed to cause female sexual desire. Although both men and women view physical attractiveness and overall personality as sexually desirable male and female characteristics, women, but not men, view femininity as a sexually desirable female characteristic, and men, but not women, view social and financial power or status as a sexually desirable male attribute.