<p>US young adults with HIV (YAWH) face service accessibility, social, and structural challenges and are less likely to be adherent to antiretroviral therapy (ART) and achieve sustained viral suppression (SVS) than older adults. We examined factors associated with ART adherence and SVS among US YAWH aged 18-24 years taking ART using data from the 2015–2022 cycles of Medical Monitoring Project. We reported weighted prevalences of 100% ART dose adherence over the past 30 days and SVS over the past 12 months with 95% confidence intervals (CIs). We estimated prevalence ratios (PRs) to assess associations (p &lt; 0.05) between adherence and SVS with key social and structural factors and health-related needs. During 2015–2022, 36.1% of YAWH were adherent and 42.9% achieved SVS. Black/African American and Hispanic/Latino YAWH were less likely to be ART adherent than White YAWH. ART adherence was less likely among YAWH who experienced homelessness, food insecurity, &gt;1 unmet subsistence service needs, and &gt; 1 non-HIV medical care services unmet need. Compared to White YAWH, Black/African American YAWH were less likely to achieve SVS. Not achieving SVS was associated with unemployment and homelessness. Approximately one third of YAWH had 100% ART adherence and less than half achieved SVS. There is a need for a comprehensive approach that addresses social and structural barriers to improve health outcomes among YAWH.</p>