The UNAIDS 90-90-90 treatment targets aim to dramatically increase the number of people who initiate antiretroviral therapy (ART) by 2020. Greater understanding of barriers to ART initiation in high prevalence countries like South Africa is critical. Qualitative semi-structured interviews were conducted with 30 participants in Gugulethu Township, South Africa, including 10 healthcare providers and 20 people living with HIV (PLWH) who did not initiate ART. Interviews explored barriers to ART initiation and acceptability of theory-based intervention strategies to optimize ART initiation. An inductive content analytic approach was applied to the data. Consistent with the Theory of Triadic Influence, barriers to ART initiation were identified at the individual, social, and structural levels. Results suggested high acceptability for intervention strategies involving trained HIV-positive peers among South African PLWH and healthcare providers. Research is needed to evaluate their feasibility and efficacy in high HIV prevalence countries.