Benefits of anti-retroviral therapy (ART) depend on consistent HIV care attendance. However, appointment non-adherence (i.e. missed appointments) is common even in programs that reduce financial barriers. Demographic, health/treatment, and psychosocial contributors to appointment non-adherence were examined among men who have sex with men (MSM) attending HIV primary care. Participants (n = 503) completed questionnaires, and HIV biomarker data were extracted from medical records. At 12 months, records were reviewed to assess HIV primary care appointment non-adherence. Among MSM, 31.2% missed without cancellation at least one appointment during 12-month study period. Independent predictors (P < 0.05) were: low income (OR = 1.87); African American (OR = 3.00) and Hispanic/Latino (OR = 4.31) relative to non-Hispanic White; depression (OR = 2.01); and low expectancy for appointments to prevent/treat infection (OR = 2.38), whereas private insurance (OR = 0.48) and older age (OR = 0.94) predicted lower risk. Low self-efficacy predicted marginal risk (OR = 2.74, P = 0.10). The following did not independently predict risk for non-adherence: education, relationship status, general health, time since HIV diagnosis, ART history, post-traumatic stress disorder, HIV stigma, or supportive clinic staff. Appointment non-adherence is prevalent, particularly among younger and racial/ethnic minority MSM. Socioeconomic barriers, depression and low appointment expectancy and self-efficacy may be targets to increase care engagement.