Youth living with HIV (YLHIV) in the southern United States experience poor outcomes across the HIV care continuum and are at high-risk for virologic failure. This study used a qualitative, community-engaged approach to inform the development of a tailored mobile Health (mHealth) tool for YLHIV in South Carolina (SC). Semistructured qualitative interviews were conducted with YLHIV in SC (n = 16) and their HIV care providers (n = 15). Focus group discussions (FGDs) were also conducted with HIV-focused community-based organization staff (n = 23). Interviews and FGDs queried desired components for a future mHealth tool tailored for YLHIV. Data were analyzed using a team-based rapid qualitative approach. Across informants, key themes emerged related to medical management of HIV, including a desire for connections with medical providers, appointment and medication reminders, and accurate HIV information. In addition, informants voiced a desire for mental health resources to be integrated into the app. Connection with HIV-positive peers also emerged as a key desire from youth informants. In terms of app design, informants emphasized the need for strict privacy practices, a youth-friendly design, compensation for use, and integration with existing healthcare systems. mHealth interventions developed for YLHIV should meet the mental health and social needs of YLHIV in addition to their medical needs. In addition, the highly stigmatized nature of HIV requires careful consideration when designing digital tools-youth want their privacy prioritized, but also express strong desire for social support to help cope with the isolation and stigma of this chronic health condition.