This study set out to determine the efficacy of a school-based early intervention program (the Kiwi ACE program) with Māori and Pacific adolescents experiencing depressive symptoms. A large group (N = 419) of Māori and Pacific students (average age 14 years) was screened for depressive symptoms and, from a pool of students scoring greater than 63 on the Children's Depression Inventory (CDI), 56 students were randomly assigned to either an intervention or control group. After attrition, the final sample constituted 24 young people after one year. The intervention comprised eight 90-minute sessions conducted in school time. Students were taught to more fully understand the relationships between thinking, feeling and behaviour, to challenge beliefs and to solve interpersonal problems. At immediate posttest (p = .045) and at one-year follow-up (p < .001) a significant effect for condition was obtained: the intervention group reported lower depressive symptoms. Efficacy of the intervention was supported by qualitative data obtained from focus groups. Further controlled trials on a larger scale are recommended to establish the durability and generalisability of the effects of program participation.