India's National AIDS Control Organization provides free antiretroviral treatment (ART) to people living with HIV (PLHIV), including members of marginalized groups such as injecting drug users (IDUs). To help inform development of interventions to enhance ART access, we explored barriers to free ART access at government ART centers for IDUs living with HIV in Chennai by conducting three focus groups (n = 19 IDUs) and four key informant interviews. Data were explored using framework analysis to identify categories and derive themes. We found interrelated barriers at the family and social, health-care system, and individual levels. Family and social level barriers included lack of family support and fear of societal discrimination, as well as unmet basic needs, including food and shelter. Health-care system barriers included actual or perceived unfriendly hospital environment and procedures such as requiring proof of address and identity from PLHIV, including homeless IDUs; provider perception that IDUs will not adhere to ART, resulting in ART not being initiated; actual or perceived inadequate counseling services and lack of confidentiality; and lack of effective linkages between ART centers, needle/syringe programs, and drug dependence treatment centers. Individual-level barriers included active drug use, lack of self-efficacy in ART adherence, low motivation to initiate ART stemming from a fatalistic attitude, and inadequate knowledge about ART. These findings indicate that to facilitate IDUs gaining access to ART, systemic changes are needed, including steps to make the environment and procedures at government ART centers more IDU-friendly and steps to decrease HIV- and drug use-related stigma and discrimination faced by IDUs from the general public and health-care providers. Housing support for homeless IDUs and linkage of IDUs with drug dependence treatment are also essential.