The importance of antiretroviral therapy adherence for patients living with HIV/AIDS has been well documented. Despite this critical need, many do not follow prescribed regimens. To examine the barriers that lead to non-adherence, we used cross-sectional survey data from a randomized controlled intervention trial in northern and north-eastern Thailand. Of the 507 patients that were enrolled in the trial, we analyzed 386 patients on antiretroviral therapy in order to examine the barriers to adherence. In addition to demographic characteristics, depressive symptoms, physical health, access to care, social support, and internalized shame, HIV disclosure and family communication were examined. The correlation analysis revealed that adherence is significantly associated with internalized shame, access to care, depressive symptoms, and family communication. Based on the multiple logistic regression analysis, depressive symptoms, access to care, HIV disclosure, and family communication were significant predictors of adherence. Having depressive symptoms remains a significant barrier to adherence, while access to care, HIV disclosure, and family communication play important positive roles. Our findings underscore the critical importance of addressing these various challenges that can influence adherence to antiretroviral therapy.