People living with HIV have high rates of obesity and obesity-related comorbidities. Our study sought to evaluate weight trajectory in a retrospective cohort of people living with HIV and matched HIV-negative veterans (controls) and to evaluate risk factors for weight gain. This was a retrospective database analysis of data extracted from the VA Corporate Data Warehouse that included people living with HIV (n=22 421) and age-matched HIV-negative controls (n=63 072). The main outcomes were baseline body weight and weight change from baseline at 1, 2, and 5 years after diagnosis (baseline visit for controls). Body weight at baseline was lower in people living with HIV than in controls. People living with HIV on antiretroviral therapy (ART) gained more weight than did controls. In a sub-analysis of ART-exposed people living with HIV, age >50 years, African American race, body mass index (BMI) <25, CD4 ≤200, and HIV diagnosis year after 2000 were associated with more weight gain at year 1. Nucleoside reverse transcriptase inhibitors (NRTI)plus non-NRTIs (NNRTIs) were associated with less weight gain than NRTIs plus protease inhibitors, NRTIs plus integrase inhibitors, or NRTIs plus other agents at year 1. Among US veterans, those living with HIV had lower rates of obesity than age-matched HIV-negative controls; however, primarily in the first 2 years after starting ART, people living with HIV gained more weight than did controls.