INTRODUCTION: Adolescents living with HIV (ALWH) experience higher mortality rates compared to other age groups, exacerbated by the suboptimal transition from paediatric to adult HIV care, during which decreased adherence to antiretroviral therapy (ART) and unsuppressed viremia are frequent. Care transition-a process lasting months or years-ideally prepares ALWH for adult care and can be improved by interventions that are youth-friendly and address psychosocial issues affecting ART adherence; however, such interventions are infrequently operationalized. Community-based accompaniment (CBA), in which laypeople provide individualized support and health system navigation, can improve health outcomes among adults with HIV. Here, we describe patient and provider perceptions of a novel HIV CBA intervention called "PASEO" for ALWH in Lima, Peru. METHODS: PASEO consisted of six core elements designed to support ALWH during and after the transition to adult HIV care. During 2019-2021, community-based health workers provided tailored accompaniment for ALWH aged 15-21 years over 9 months, after which adolescent participants were invited to provide feedback in a focus group or in-depth interview. HIV care personnel were also interviewed to understand their perspectives on PASEO. A semi-structured interview guide probing known acceptability constructs was used. Qualitative data were analysed using a framework analysis approach and emergent themes were summarized with illustrative quotes. RESULTS: We conducted five focus groups and 11 in-depth interviews among N = 26 ALWH and nine key-informant interviews with HIV care personnel. ALWH participants included males, females and one transgender female, and those with both early childhood and recent HIV infection. ALWH praised PASEO, attributing increased ART adherence to the project. Improved mental health, independence, self-acceptance and knowledge on how to manage their HIV were frequently cited. HIV professionals similarly voiced strong support for PASEO. Both ALWH and HIV professionals expressed hope that PASEO would be scaled. HIV professionals voiced concerns regarding financing PASEO in the future. CONCLUSIONS: A multicomponent CBA intervention to increase ART adherence among ALWH in Peru was highly acceptable by ALWH and HIV programme personnel. Future research should determine the efficacy and economic impact of the intervention.