Psychosocial syndemic conditions have received more attention regarding their deleterious effects on HIV acquisition risk than for their potential impact on HIV treatment and viral suppression. To examine syndemic conditions' impact on the HIV care continuum, we analyzed data collected from people living with HIV (N = 14,261) receiving care through The Centers for AIDS Research Network of Integrated Clinical Systems at seven sites from 2007 to 2017 who provided patient-reported outcomes ∼4-6 months apart. Syndemic condition count (depression, anxiety, substance use, and hazardous drinking), sexual risk group, and time in care were modeled to predict antiretroviral therapy (ART) adherence and viral suppression (HIV RNA <400 copies/mL) using multilevel logistic regression. Comparing patients with each other, odds of ART adherence were 61.6% lower per between-patient syndemic condition [adjusted odds ratio (AOR) = 0.384; 95% confidence interval (CI), 0.362-0.408]; comparing patients with themselves, odds of ART adherence were 36.4% lower per within-patient syndemic condition (AOR = 0.636 95% CI, 0.606-0.667). Odds of viral suppression were 29.3% lower per between-patient syndemic condition (AOR = 0.707; 95% CI, 0.644-0.778) and 27.7% lower per within-patient syndemic condition (AOR = 0.723; 95% CI, 0.671-0.780). Controlling for the effects of adherence (AOR = 5.522; 95% CI, 4.67-6.53), each additional clinic visit was associated with 1.296 times higher odds of viral suppression (AOR = 1.296; 95% CI, 1.22-1.38), but syndemic conditions were not significant. Deploying effective interventions within clinics to identify and treat syndemic conditions and bolster ART adherence and continued engagement in care can help control the HIV epidemic, even within academic medical settings in the era of increasingly potent ART.