Although anticipated HIV-related stigma-the expectation that one will experience prejudice and discrimination in the future as a result of others learning his or her HIV positive status-is theorized to be a robust predictor of antiretroviral therapy (ART) non-adherence, the association between anticipated stigma and ART non-adherence has been inconsistent. It may be, however, that anticipated stigma reliably, but indirectly, contributes to poor ART adherence through other psychosocial mechanisms. In the current study, we examine whether anticipated stigma indirectly contributes to treatment non-adherence through increased medication concerns. In a cross-sectional study, 585 people living with HIV in Atlanta and Macon, Georgia completed measures of anticipated HIV-related stigma, HIV-medication concerns, and HIV-treatment adherence. A latent variable mediation analysis revealed that anticipated stigma was positively associated with increased medication concerns, which consequently contributed to treatment non-adherence. Results reveal a psychosocial mechanism by which anticipated stigma contributes to ART non-adherence.