Background: It is widely accepted that for HIV-positive persons on highly active antiretroviral treatment, high levels of adherence to treatment regimens are essential for promoting viral suppression and preventing drug resistance. Objectives: This qualitative study examines factors affecting the adherence to HIV/AIDS treatment among patients with HIV/AIDS at a local hospital in Malaysia. Methods: The data from purposefully selected patients were collected by in-depth interviews using a pretested interview guide. Saturation was reached at the 13th interview. All interviews were audio-taped and transcribed verbatim for analysis using thematic content analysis. Results: Fear and stigma of perceived negative image of HIV diagnosis, lack of disease understating, poor support from the community, and perceived severity or the treatment side effects were among the reasons of nonadherence. Appropriate education and motivation from the doctors and reduction in pill burden were suggested to improve adherence. Conclusion: Educational interventions, self-management, and peer and community supports were among the factors suggested to improve adherence. This necessitates uncovering efficient ways to boost doctor-patient communication and recognizing the role of support group for the social and psychological well-being of the patients.