Background: Behavioural Activation (BA) is an evidence-based psychological treatment for depression based on behavioural theory. However, in common with other talking therapies, there is limited evidence about occupational factors related to treatment. This is an important gap in the research given the emphasis placed on employment considerations in recent service initiatives. Aim: A service evaluation to investigate the clinical and fitness to work outcomes of a group BA programme for serving military personnel. Method: 46 patients experiencing moderate to severe depression attended a 12-session Military Behavioural Activation and Rehabilitation Course (MBARC). The primary outcomes were the Patient Health Questionnaire-9 (PHQ-9), a self-report measure of depression and the patient's medical employability category. Results: Clinical and statistically significant changes were found on the PHQ-9 between pre-course and 3-month follow-up. Pretreatment 3 patients (6.5%) were psychologically fit to deploy on full operational duties in their primary role; this increased to 25 (56.8%) and 29 (65.9%) at 3 and 6-months respectively. Conclusion: Preliminary findings suggest that MBARC is a clinically and occupationally effective treatment for depression in military personnel. Further research is required to identify if BA delivered in a group setting would be effective in non-military settings and whether treatment benefits are maintained in the longer term.