Although gender-specific theories are often deployed in interventions to reduce women's HIV risks, the same is often not true for interventions among men. Theories of masculinity are not guiding most US research on the risky sexual behavior of heterosexual men or on what can be done to intervene. We first assess the extent to which evidence-based HIV-prevention interventions among heterosexually active men in the United States draw upon relevant theories of masculinity. Next, we introduce a useful framework within masculinity and gender studies that can be applied to HIV-prevention interventions with heterosexually active men. Finally, we make suggestions to improve the gender specificity of HIV-prevention interventions for heterosexually active men in the United States.