OBJECTIVE: Among gay, bisexual, and other men who have sex with men, intrusive sexual thoughts/behaviors (i.e., distress about one's sexual urges or behaviors) are associated with depression and engagement in behavior that increases the risk for sexually transmitted infections (STIs). The present study examines the association between internalized homonegativity and intrusive sexual thoughts/behaviors, the intervening effect of depression symptoms, and the potential buffering effect of social support. Furthermore, we establish the subsequent link with physical health outcomes by examining the association between intrusive sexual thoughts/behaviors and recent bacterial STI diagnosis. METHOD: Using participant data ( RESULTS: Higher internalized homonegativity scores conditionally predicted greater intrusive sexual thoughts/behaviors 1 year later: participants with higher internalized homonegativity scores reported more severe intrusive sexual thoughts/behaviors if they also had lower social support, β = .08, CONCLUSION: Given that social support mitigated the impact of internalized homonegativity on intrusive sexual thoughts/behaviors, ultimately indirectly reducing the occurrence of bacterial STIs in this population, these findings demonstrate the utility of psychosocial factors as potential intervention targets for improving the health of gay, bisexual, and other men who have sex with men. (PsycInfo Database Record (c) 2025 APA, all rights reserved).