BackgroundYouth with severe emotional or behavioral issues who are involved with child welfare authorities are sometimes placed in intensive care services in a residential treatment program. Evidence-based psychotherapies are often used in residential treatments, but there is very little research on how to adapt psychotherapy for residential treatment. ObjectiveTo describe the implementation of a transdiagnostic cognitive behavioral therapy (the Unified Protocol for Transdiagnostic Treatment of Emotional Disorders in Children) in a residential treatment program for children. Participants and settingStaff (n = 20) at a residential facility in Calgary, Canada. MethodsA combination of qualitative interviews and focus groups were conducted before and after therapy to identify barriers and facilitators to implementation. Data were analyzed and reported using the Consolidated Framework for Implementation Research and the Framework for Reporting Adaptations and Modifications to Evidence-based Implementation Strategies. ResultsModifications were made to the program including creating inclusive language, integrating relevant content targeting pediatric irritability, delivering sessions online for caregivers, and using additional staff to support youth to learn and practice the application of the content and behavioral interventions. Key barriers to implementation of the Unified Protocol included staff turnover and the difficulty of sustaining a critical mass of knowledge surrounding the Unified Protocol. The major facilitators to implementation were the perceived quality of the program and advantages of the program to children and their caregivers. ConclusionsThis study supports the feasibility and acceptability of providing transdiagnostic cognitive behavioral therapies for children in residential treatment and provides a template for how to implement evidence-based practice in residential treatment.