Substance use problems undermine HIV treatment and secondary prevention efforts. Research is needed to better understand predictors of substance use among people living with HIV (PLWH). We examined whether internalized stigma and enacted HIV stigma are associated with three indicators of substance use among PLWH, including numbers of (1) substances used, (2) substances used at moderate to high risk, and (3) times substances were used before sex, through the mediator of depressive symptoms. Participants included 358 PLWH aged 18-35 years from Georgia, United States. At baseline, participants completed measures of internalized and enacted stigma, depressive symptoms, and substance use severity. Substance use was additionally tested with urinalysis. Following baseline, participants reported their use of substances before sex for 28 days through daily text messaging. Data were analyzed using path analysis in R. On average, participants tested positive for 1.24 (range: 0-6) substances used, reported moderate to high risk on 2.01 (range: 0-8) substances, and reported using substances 1.57 (range: 0-20) times before sex over 28 days. Internalized stigma and enacted stigma were associated with greater depressive symptoms, and depressive symptoms were associated with all three indicators of substance use. Moreover, the indirect effects between internalized and enacted stigma with indicators of substance use were significant, suggesting that depressive symptoms partially mediated associations between stigma and substance use. Interventions may be needed to address both stigma and depressive symptoms among PLWH to reduce substance use and support HIV treatment and prevention efforts.