Background: Individuals with opioid dependence experience stigma and discrimination. Stigma can potentially reduce treatment-seeking and negatively affect treatment outcomes. We aimed to study the course of stigma and its correlates among patients receiving opioid agonist treatment (OAT). Methods: We recruited 51 subjects (aged between 18 and 45 years) registered in the OAT clinic from February to September 2019. We excluded subjects dependent on alcohol and other drugs (except for cannabis and tobacco), with severe mental illness, intellectual disability, and organic brain disease. We assessed the internalized and enacted stigma and quality of life at the treatment entry and after 3 months. Relationship of stigma with quality of life, socio-demographic, and other clinical variables were examined at the treatment entry. Results: Mean age of the subjects was 26.7 (± 5) years. At the end of three months, 33 (64.7%) patients were retained in the treatment. Internalized stigma correlated negatively with the social and environmental domains of quality of life. The strength of the correlations was modest. No significant correlation was found between demographic and clinical variables and internalized stigma and enacted stigma scores. Both internalized and enacted stigma scores reduced significantly at 3 months follow-up. The significance levels were retained even after controlling for the baseline quality of life scores. Stigma at the treatment entry did not predict early dropout. Conclusion: Despite higher severity at the treatment entry, the level of internalized and enacted stigma reduced significantly within three months of an outpatient-based OAT program.