Middle-aged and older gay men experience higher rates of depression and anxiety compared to their heterosexual counterparts, with internalized homonegativity and sexual identity concealment known to be major stress-related contributors. This study examined the prospective effect of different types and sources of social support on internalized homonegativity and sexual identity concealment experienced among middle-aged and older gay men.A longitudinal survey involving two waves of data collection separated by 12 months was conducted among a cohort of 186 gay-identified men aged 40 years and older.Two types of social support were found to be important. Greater baseline tangible or practical support independently predicted lower internalized homonegativity at 12-month follow-up, while greater baseline emotional or psychological support independently predicted a lower tendency toward sexual identity concealment at 12-month follow-up. Greater baseline support from community or government agencies, such as health services and support organizations, predicted higher internalized homonegativity at 12-month follow-up.These findings suggest that tangible and emotional support may be beneficial in reducing internalized homonegativity and sexual identity concealment among middle-aged and older gay men. Ensuring that services provide environments that do not compound the stressful impact of stigma also appears to be important.