Despite the successful rollout of antiretroviral therapy (ART) and positive ART outcomes in the Kingdom of Eswatini, adolescents still present poor ART outcomes including low viral load suppression and suboptimal ART adherence. The aim of the study was to explore the perceptions of adolescents living with HIV (ALHIV) on the barriers and facilitators to ART adherence in Eswatini. We conducted a qualitative study using in-depth interviews among 29 ALHIV and on ART in Eswatini in December 2023. Adolescents aged 10-19 years who were aware of their HIV status were recruited purposively from five Teen Clubs in the Hhohho region. Six barriers to ART were reported by participants namely perceived stigma and discrimination, competing demands between ART schedules and their personal and social lives, medication issues, health facility factors, lack of transport and food, and diminishing support from caregivers. The main facilitators of ART adherence were having a social support system, status disclosure, privacy, HIV and ART knowledge, and motivation to stay alive. Supportive environments are crucial to enhance ART adherence among ALHIV. These can be promoted through multi-component interventions that target status disclosure, increase knowledge of HIV and ART, ensure privacy and address stigma and discrimination.