Several methodological gaps exist regarding assessing the relationship between antiretroviral therapy (ART) and mental health. Adopting an "HIV care continuum" perspective, cross-sectional data from 2987 people living with HIV (PLHIV) in Guangxi, China were used. ART uptake was retrieved from medical records and ART adherence was self-reported (good vs. poor adherence with a percent adherence cut-off of 90%). Depression, anxiety, and mental-health related quality of life were used as mental health indicators. Separate analysis was conducted for ART uptake and ART adherence. Differences in mental health were investigated using multivariate analysis of variance (MANOVA). Multivariate analysis of covariance (MANCOVA) adjusting for propensity scores was further conducted. MANCOVA results showed statistically significant multivariate effects for ART adherence (Wilk's lambda = 0.984, F [3, 1885] =10.26, p<0.001) but not ART uptake (Wilk's lambda = 0.998, F [3, 2476] =1.67, p=0.17). Post-hoc comparisons with Bonferroni adjustment (alpha=0.05/3 = 0.0167) showed that well-adherent ART users had lower scores on anxiety (p=0.006) and higher scores on MHS (p=0.007), but no difference was found for depression (p=0.023). As only ART adherence was associated with better mental health among PLHIV, to maximize the potential mental health benefits of ART, intervention efforts need to emphasize on treatment adherence.