Background: There is an urgent need for evidence-based, scalable, psychological interventions to improve the mental health of adolescents affected by adversity in low-resource settings. Early Adolescents Skills for Emotions (EASE) was developed by the WHO as a brief, transdiagnostic, group intervention for early adolescents exhibiting internalising problems, delivered by trained and supervised lay providers. This study describes the cultural adaptation of EASE for Burundian adolescents living in Mtendeli refugee camps in Tanzania. Methods: A phased approach to adaptation of the EASE intervention and its implementation, was adopted and comprised of: (1) a desk review to synthesize existing research on mental health issues in conflict-affected Burundian communities, (2) a rapid qualitative assessment involving free listing and key informant interviews with multiple stakeholders, (3) cognitive interviews with end users, and (4) a two-part adaptation workshop involving the implementing partner staff, members of the refugee community and mental health experts. We applied the Bernal framework to systematically document and track adaptations across eight dimensions of the intervention. Results: Problems associated with worry, stress, sadness, shame and fear were identified as amongst the most critical mental health concerns, alongside a range of experiences of different forms of violence (such as gender-based violence, violence when fleeing from their homes) and associated problems. Problems associated with violence that included past experiences of fleeing as well as ongoing problems of gender-based violence in the camp. The most significant adaptations that were required included providing options for low literacy of participants, safety planning to address the high prevalence of sexual violence, simplification of strategies for the benefit of the end users and of lay facilitators, and implementation changes to consider involvement of refugee incentive workers. A majority of changes were across dimensions of language, people, metaphors, content, methods and context, while there were fewer changes regarding the goals and concepts of EASE. Conclusions: The approach to adaptation of a psychological intervention suggested both minor and major required changes. Adaptations based on the findings of this study are anticipated to enhance relevance and acceptability of the EASE intervention and its delivery for camp-residing Burundian refugees in Tanzania.