Lesbian, gay, and bisexual (LGB) individuals are at higher risk for poor mental health than their heterosexual counterparts, and these disparities are largely accounted for by minority stressors. Less is known about the mechanisms underlying associations between minority stress and mental health. In a sample of 592 LGB adults (Mage = 29.39), we tested a model in which minority stress (internalized stigma, stigma consciousness, and lived discrimination) was associated with poor mental health when mediated by stigma-related barriers to accessing psychological services. Structural equation modeling revealed that minority stressors predicted more barriers to service use which, in turn, predicted poorer mental health outcomes. Internalized stigma was also directly associated with poor mental health. Results suggest that links between minority stress and poorer mental health in LGB individuals are at least partly explained by stigma-related barriers to accessing services. Future research is needed to investigate methods which may ameliorate these barriers.