Background Developing low-cost, socio-culturally appropriate, and scalable interventions for youth depression and anxiety symptoms in low-income regions such as countries in Sub Saharan Africa is a global mental health priority. We developed and intend to evaluate one such intervention for adolescent depression and anxiety in Kenya. The intervention, named Shamiri (a Swahili word for ‘thrive’), draws upon evidence-based components of brief interventions that involve nonclinical principles rather than treatment of psychopathology (e.g. growth mindset, gratitude and virtues).Methods 420 Kenyan adolescents (ages 13-18) with clinically elevated depression and/or anxiety symptoms will be randomized to either the four-week Shamiri group intervention or a group study-skills control intervention of equal duration and dosage. Participating adolescents will meet in groups of 8-15, led by a high-school graduate trained to deliver Shamiri as a lay-provider. Adolescents will self-report primary outcome measures (depression—measured by the PHQ-8, and anxiety symptoms—measured by the GAD-7) and secondary outcome measures (perceived social support, perceived academic control, self-reported optimism and happiness, loneliness, and academic grades) at the 2-week intervention midpoint, 4-week post-intervention endpoint, and 2-week post-intervention follow-up. We predict that adolescents in the Shamiri group, when compared to the study-skills control group, will show greater improvements in primary outcomes and secondary outcomes. Discussion Results may suggest that a brief, lay-provider delivered, school-based intervention may reduce depression and anxiety symptoms, improve academic outcomes and other psychosocial outcomes in adolescents with clinically-elevated symptoms in Sub-Saharan Africa.Trial RegistrationPan African Clinical Trials Registry. Trial ID: PACTR201906525818462. Registered 12th June 2019.