Background In Mexico, the quality of health care for human immunodeficiency virus (HIV) patients is unknown. The study objectives were to develop quality of care (QoC) indicators for outpatient care of HIV patients, evaluate the quality of the processes of care (QPC) and outcomes, and analyze the association between the QPC and viral suppression among HIV patients. Methods The study used a mixed-methods approach: (1) Development of QoC indicators through RAND/UCLA method; (2) cross-sectional study of QoC evaluation; and (3) multiple Poisson regressions to measure the association between the QPC and viral suppression. The study included 439 HIV patients, ≥ 19 years of age, with at least one outpatient consultation during 2017 at a public hospital in the State of Mexico. Results We developed 21 QoC indicators to evaluate HIV care. Based on these indicators, the QoC gaps that emerged were related to clinical history (24% of patient records included sexual history information), routine adherence assessment (no records demonstrated regular recording of antiretroviral treatment adherence), and screening and referral (50% were screened for depression, and 42% for tuberculosis; 1.2% of patients with abnormal body mass index were referred to a dietitian). On average, HIV patients received 63% of recommended QPC; 77.7% achieved viral suppression. Receiving over 75% of recommended QPC was associated with a higher probability of viral suppression (adjusted prevalence ratio 1.13, 95% confidence interval 1.03-1.24). Conclusions Evaluation of the QoC for HIV patients is essential to identify and address gaps in health-care quality to increase the probability of viral suppression.