The Minority Stress model posits that sexual minorities experience stressors related to their marginalized identities that lead to health disparities. Previous research has examined the association between minority stress and problematic drinking in sexual minorities; however, individual risk factors that have been linked to problematic drinking in presumably heterosexual samples, such as impulsivity and drinking motives, have been largely ignored in the minority stress literature. In light of the aforementioned gaps, the study had two aims: (1) Examine how impulsivity and drinking to cope motives moderate the relationship between sexual minority stressors and problematic drinking; and (2) Examine the relationship between impulsivity and other known health factors in an integrative psychosocial model of problematic drinking in sexual minorities. Sexual minorities (n = 471) were recruited through an online panel service. Participants completed an online survey that assessed sexual minority stressors, problematic drinking, interpersonal processes, negative affect, impulsivity, and drinking motives. Results supported a model showing that internalized homonegativity, social isolation, and drinking to cope motives significantly mediated the association between sexual orientation discrimination and problematic drinking (total indirect effect: β = 0.19). Moderated mediation analyses also revealed that a Drinking to Cope Motives x Internalized Homonegativity interaction was significantly associated with problematic drinking (β = 0.09), such that the indirect effect was significant for high (β = 0.07), average (β = 0.06), and low values of positive urgency (β = 0.05). These findings suggest that the aforementioned indirect effect through drinking to cope motives was significantly more positive at higher levels of positive urgency. This study provided support for the importance of impulsivity in the pathways between minority stressors and problematic drinking.