Symptoms of depression are common in adolescents and have negative impacts on academic engagement and achievement, as well as on future mental health and functioning. A number of psychological therapies are effective for the treatment of adolescent depression but there are barriers to young people accessing treatment promptly. Providing treatment in school may help improve access to mental health care; school-based mental health care is routinely provided in some parts of the world and is currently a policy priority in the UK. However, introducing mental health services into schools will require services to adapt. This paper illustrates how a short-term psychological therapy can be delivered successfully in schools. It describes the treatment and outcomes for two young people with symptoms of depression. Both received Brief Behavioural Activation (Brief BA) which has been adapted specifically for adolescents. Brief BA focuses on helping young people engage with valued activities in different areas of their life, thus increasing rewards and reducing symptoms of depression. The two cases highlight a range of educational and clinical benefits of Brief BA for young people with depression symptoms and illustrate how the treatment and service delivery were adapted for schools.