Internalized heterosexism (IH) is a strong predictor of the psychological well-being of lesbian, gay, bisexual (LGB), or other same-sex attracted individuals. To respond to the call for interventions to address IH, the current study developed and tested an online intervention to reduce IH among gay, bisexual, and other same-sex attracted men. A total of 367 self-identified same-sex attracted adult males were recruited through various nationwide LGB-related sources and were assigned by birth month to either the experimental condition (focusing on IH reduction) or the control condition (a similarly structured invention focusing on stress management); 290 of these participants completed the intervention and all post-intervention measures. Mean levels of IH were compared by condition, indicating significant differences on the IH global score and 2 of the 3 IH subscale scores between the participants in the 2 conditions. The study findings support the promise of using the Internet to deliver IH interventions. Implications for research and practice are discussed. (Contains 3 tables.)