Incarcerated individuals, who are overrepresented among those infected with HIV, experience multiple barriers to optimal antiretroviral therapy (ART) adherence after incarceration. Substance use is highly prevalent among legal system-involved individuals and is commonly associated with suboptimal medication adherence. This manuscript describes the development and pilot test results of two interventions designed to improve ART adherence among formerly incarcerated individuals living with HIV (PLWH). Thirty participants were randomized and completed a multi-session ART adherence and risk reduction intervention or a brief ART adherence intervention. Participants were interviewed at baseline, 1-month, and 3-month follow-up. While past 30-day ART adherence improved in both groups, participants in the brief intervention group took a higher proportion of their ART medication. Multi-session intervention group participants experienced greater reductions in substance use and problematic experiences associated with drug use. ART medication adherence interventions can potentially improve treatment outcomes among PLWH who experience incarceration.