Questions: What is the reach, dose delivered, dose received and fidelity of the Transmural Trauma Care Model (TTCM)? What are the barriers and facilitators associated with the implementation of the TTCM? Design: Mixed-methods process evaluation with quantitative evaluation of the extent to which the TTCM was implemented as intended and qualitative evaluation of barriers and facilitators to its implementation. Participants: Focus group participants included trauma patients, trauma surgeons, hospital-based physiotherapists and primary care network physiotherapists. Outcome measures: Implementation was assessed with reach, dose delivered, dose received and fidelity. Data analysis: A framework method was used to analyse the focus groups and the ‘constellation approach’ was used to categorise barriers and facilitators into three categories: structure, culture and practice. Results: The TTCM's reach was 81%, its dose delivered was 99% and 100%, and its dose received was 95% and 96% for the multidisciplinary TTCM consultation hours at the outpatient clinic for trauma patients and the primary care network physiotherapists, respectively. Various fidelity scores ranged from 66 to 93%. Numerous barriers and facilitators associated with the implementation of the TTCM were identified and categorised. Conclusion: This process evaluation showed that the TTCM was largely implemented as intended. Furthermore, various facilitators and barriers were identified that need to be considered when implementing the TTCM more widely. Differences were found among stakeholders but they were generally of the opinion that if the barriers were overcome, the quality of care and patient satisfaction were likely to improve significantly after implementing the TTCM. Registration: NTR5474.