Abstract Background In Colombia, over 9 million people have been impacted by armed conflict, creating a significant need for mental health services. This study aimed to culturally adapt and pilot test the Youth Readiness Intervention (YRI), an evidence-based transdiagnostic mental health intervention, for conflict-affected Colombian youth aged 18-28 years. Methods The eight phases of the Assessment, Decision, Administration, Production, Topical Experts, Integration, Training, and Testing (ADAPT-ITT) framework were used to culturally adapt the YRI for conflict-affected Colombian youth. The Framework for Reporting Adaptations and Modifications to Evidence-based Implementation Strategies (FRAME-IS) was used to track the adaptations made. Qualitative and quantitative data were gathered and analyzed throughout the adaptation process. Results Data from the Assessment phase demonstrated a high need for mental health interventions among conflict-affected youth. The Testing phase revealed significant improvements in emotion regulation and functional impairment, suggesting the YRI is a promising intervention among conflict-affected Colombian youth. Qualitative data confirmed the intervention’s acceptability among youth and mental health providers. Conclusions The YRI was successfully adapted for conflict-affected Colombian youth. Future studies using randomized designs are needed to test the effectiveness of the YRI for improving mental health among larger samples of Colombian conflict-affected youth.