A large body of research identifies depressive symptoms as a barrier to optimal antiretroviral therapy (ART) adherence, whereas treatment motivation has been characterized as a facilitator. There is evidence, however, that these patterns may not hold for some ART patients despite the widespread use of motivational techniques aimed at promoting adherence. Little is known about how the interplay between different levels of depressive symptoms and variations in the types and levels of motivation may influence ART adherence. The purpose of this study was to examine the relationship between depressive symptoms, two types of motivation, and adherence, with self-efficacy as a mediator. The sample consisted of 121 ART patients who reported various levels of depressive symptoms (mean age = 41 years; 84% African-American; and 68% female). Path analysis revealed that self-efficacy fully mediated the relationship between the three predictor variables (depressive symptoms, intrinsic motivation, and extrinsic motivation) and adherence, χ(3, N = 121) = .78, RMSEA = .00, SRMR = .02, CFI = 1.00, NNFI = 1.06. Findings suggest that interventions using motivational techniques to build adherence among patients with varying levels of depressive symptoms should address the role of treatment self-efficacy to improve their effectiveness.