Currently, the evolution in Antiretroviral (ARV) treatment has been remarkable. It has transformed Human immunodeficiency virus (HIV) from a fatal illness into a manageable chronic condition and led to a significant increase in the lifespan of HIV-infected patients. Hence, improving the quality of life (QOL) of people living with HIV is a critical aspect of HIV management. In Vietnam, the rate of HIV infection in the group of men who have sex with men (MSM) has rapidly increased in recent years. Therefore, the authors conducted the study to determine the scores and evaluate some factors related to the QOL of the MSM group infected with HIV who are being treated at a private outpatient clinic in Ho Chi Minh City. 199 HIV-infected MSM patients who underwent ARV treatment at the outpatient Glink clinic from April 2023 to April 2024 were recruited to the study. The measurement tools include the World Health Organization’s QOL assessment questionnaire (WHOQOL-HIV BREF) and a questionnaire that collects general information about the population, society, and some factors related to HIV disease. The study results show that most patients perceive their current QOL as good at 89.9%, with a mean score of 3.53 ± 0.71. The median QOL scores in the six domains of physical health, psychological health, level of independence, spirituality, social relationships, and environment are 16.0 (IQR: 14.0-17.0), 15.2 (IQR: 13.6-16.0), 16.0 (IQR: 15.0-16.0), 12.0 (IQR: 11.0-13.0), 13.5 (IQR: 12.5-15.0), respectively. Some factors related to the QOL include age, duration of ARV treatment, mental health issues, etc. The study findings suggest that to improve the QOL of this population group, there needs to be a greater focus on strengthening social connections, family support, and effective management of mental health issues.