There is minimal research that has been conducted among young adults to understand the determinants of the utilization of human immunodeficiency virus (HIV) health services in this population. The purpose of this study was to explore the levels and determinants of HIV transition clinic (HTC) services utilization by young adults living with HIV/acquired immunodeficiency syndrome (YALHA). The study used a cross-sectional design and quantitative methods to collect data from a sample of 379 YALHA between the ages of 15–24 years who were registered clients of an HTC in Uganda. During data analysis, utilization was categorized into two levels: regular (kept all appointment visits) and irregular (missed one or more appointment visits) utilization. Univariable, bivariable, and multivariable logistic regression analyses were used to examine the determinants associated with HTC utilization. The HTC services that were most utilized by the YALHA were those based at the clinic and provided by professional health care providers and these were: clinical examination (96%); laboratory services (87.1%); and counseling (69.7%). The services that were least utilized were home visiting (5.8%) and peer support services (19.8%). Of the 379 YALHA, only 32.4% regularly utilized the HTC. Multivariable analysis showed that the main determinants of HTC utilization were CD4 count category of =251/µL (adjusted odds ratio [AOR] =0.58, 95% confidence interval [CI] =0.36–0.95); not being on antiretroviral therapy (AOR =0.27, 95% CI =0.15–0.47); and not receiving counseling services (AOR =0.47, 95% CI =0.27–0.83). Regular utilization of the HTC by YALHA was low and utilization seems to be influenced by HIV infection stage and HIV counseling services, but not sociodemographic factors or community factors.