BACKGROUND: Black women living with HIV (WLHIV) often have suboptimal ART adherence due to a multitude of social and structural barriers, including HIV-related stigma. Trust in healthcare providers plays a significant role in adhering to ART and is likely lower among Black WLHIV compared to their White counterparts. This study examined the relationship between experienced stigma in healthcare settings and ART adherence and viral suppression through anticipated stigma in healthcare settings, internalized stigma, and medical mistrust. PARTICIPANTS/PROCEDURES: Participants included Black WLHIV from the Women's Interagency HIV Study (WIHS). We conducted serial mediation analyses where experienced HIV stigma in healthcare settings is associated with higher anticipated or internalized HIV stigma, leading to higher mistrust in HIV care providers, and ultimately, to lower ART adherence and viral suppression, adjusting for demographic and clinical covariates. RESULTS: Of the 1,060 WLHIV, approximately 84% achieved optimal ART adherence, and 65% had an undetectable viral load. Serial mediation analyses suggested significant indirect associations between experienced stigma in healthcare settings and ART adherence or viral suppression. Specifically, experienced stigma was associated with higher anticipated or internalized stigma, which was associated with mistrust in HIV care providers, resulting in lower ART adherence and reduced likelihood of undetectable viral load. CONCLUSIONS: Interventions could focus on training healthcare providers to address implicit biases and create supportive healthcare environments. Integrating mental health support to reduce internalized stigma and using community engagement and education to address anticipated stigma may further improve trust in providers, leading to better health behaviors and outcomes.