Men who have sex with men (MSM) are the group most severely impacted by HIV in the United States (CDC, 2015). Many MSM, however, still engage in sex without condoms (Smith, Herbst, Zhang, & Rose, 2015). One factor influencing a lack of condom use among MSM may be an assumption of low risk of contracting HIV or another STI from physically attractive partners. This assumption may be particularly dangerous for MSM who use geosocial networking applications (GSN) to find sexual partners. Previous researchers have suggested that this assumption could be based on two theoretical mechanisms: implicit personality theory and motivated reasoning. The present study tested two hypothesized models of the associations between physical attractiveness, perceived HIV/STI risk, and condom use intentions, based on these proposed theories. Participants were 197 MSM who completed an online survey in which they viewed photos of physically attractive and unattractive men and responded to items on perception of positive partner personality characteristics, intention to have sex with the partner, perceived risk for HIV/STIs, and condom use intentions. Results supported both theories. Specifically, physical attractiveness was negatively associated with perceived risk for HIV/STIs and condom use intentions, and these relations were mediated by intentions to have sex and positive partner personality. Implications of these findings for further research and practice are discussed.