The Ryan White HIV/AIDS program (RWHAP) provides essential primary and supplementary health services to people living with HIV (PLWH). We examined the relationship between supplementary RWHAP services (Part B) and two outcomes: viral suppression (VS) and two separate measures of retention in care (RiC) based on kept- and missed-visits. We used purposive sampling to identify adult patients who received primary medical care at an academically-affiliated HIV/AIDS clinic in the southeastern United States (N = 1159) and who attended at least one scheduled HIV primary care appointment at the study site during 2015. Unadjusted and adjusted logistic regression models were fit, in which RWHAP supplementary services were the primary independent variables of interest. Age, race, gender, education level, and income were control variables. Among 1159 PLWH, 45.3% received RWHAP supplementary services in addition to public insurance, private insurance, or primary RWHAP. Among participants, 91.4% were virally suppressed, 87.4% were retained in care using the Institute of Medicine (IOM) kept-visits measure, and 60% were retained in care using the missed-visits measure. In multivariable models, patients with RWHAP supplementary services had significantly higher odds of (1) VS [adjusted odds ratio (AOR) = 1.91], (2) RiC using the IOM kept-visits measure (AOR = 2.56), and (3) RiC using the missed-visits measure (AOR = 1.58). Receipt of supplementary RWHAP services is associated with increased odds of VS and two measures of RiC when adjusting for key sociodemographic variables. Policymakers should consider the vital role of RWHAP as continued funding is uncertain.