In Thailand, antiretroviral therapy (ART) programs still have difficulties reaching and promoting adherence among a key population - young men who have sex with men (YMSM) living with HIV. As such, we sought to examine potential psychosocial barriers that may contribute to suboptimal levels of ART adherence for this population. Data were drawn from a study of 214 YMSM living with HIV from Bangkok, Thailand. Linear regression models tested the association between depression and ART adherence, and whether social support and HIV-related stigma moderated that relationship. Multivariable models demonstrated social support was significantly associated with higher levels of ART adherence, and that there was a three-way interaction between depression, social support, and HIV-related stigma on ART adherence. These results further our understanding of the role of depression, stigma, and social support in ART adherence among Thai YMSM living with HIV, and that additional supports for YMSM with depression and HIV-related stigma are needed.