South Africa has the highest number of people with HIV (PWH) globally and a significant burden of co-occurring substance use disorder (SUD). Health care worker (HCW) stigma towards SUD is a key barrier to HIV care engagement among PWH with SUD. Support from peers—individuals with lived experience of SUD—may be a promising solution for addressing SUD stigma, while also improving engagement in HIV care. We evaluated the perceived acceptability of integrating a peer role into community-based HIV care teams as a strategy to address SUD stigma at multiple levels and improve patient engagement in HIV care. Patients and stakeholders (N = 40) were recruited from publicly-funded HIV and SUD organizations in Cape Town, South Africa. We conducted a quantitative assessment of stigma among stakeholders using an adapted Social Distance Scale (SDS) and patient perceptions of working with a peer, as well as semi-structured interviews focused on experiences of SUD stigma, acceptability of a peer model integrated into community-based HIV care, and potential peer roles. On the SDS, 75% of stakeholders had high stigma towards a patient with SUD, yet 90% had low stigma when in recovery for at least 2 years. All patients endorsed feeling comfortable talking to someone in recovery and wanting them on their HIV care team. Three main themes emerged from the qualitative data: (1) patient-reported experiences of enacted SUD and HIV stigmas were common and impacted HIV care engagement; (2) both patients and stakeholders considered a peer model highly acceptable for integration into HIV care to support engagement and address SUD stigma; and (3) patients and stakeholders identified both individual-level and systems-level roles for peers, how peers could work alongside other providers to improve patient care, and key characteristics that peers would need to be successful in these roles. Findings from this formative work point to the promise of a peer model for reducing SUD stigma among patients and HCWs within community-based HIV care teams in SA.