Older HIV-infected gay men may experience multiple forms of stigma related to sexual orientation (homonegativity), HIV (HIV stigma), and age (ageism), all of which can negatively impact quality of life (QOL). Our purpose was to determine predictors of homonegativity, internalized HIV stigma, and ageism, and stigma experiences that were predictive of QOL. Sixty HIV-infected gay men, ages 50–65 years, participated. Younger age and emotion-focused coping were significantly predictive of homonegativity, accounting for 28% of variance. Younger age, support group participation, medications per day, social support, and emotion-focused coping predicted internalized HIV stigma, accounting for 35% of variance. Problem-focused coping predicted ageism, accounting for 7% of variance. In regression analysis, the three types of stigma accounted for 39% of variance in QOL (homonegativity 19%, internalized HIV stigma 19%, ageism 0.5%). Study findings may help researchers develop interventions to alleviate multiple stigma experiences of HIV-infected older gay men, thus improving QOL.