The global population of young people aged 10-24 exceeds 1.8 billion, with 90% residing in low- and middle-income countries. Mental disorders, particularly the “common mental disorders” of depression, anxiety, and conduct disorders, are the leading cause of disability in this age group. However, the vast majority of mental health service needs for young people go unmet. The goal of the PRIDE trial is to 1) develop a transdiagnostic stepped care psychosocial intervention for common mental disorders in government-run secondary schools in New Delhi, India; and 2) evaluate its effectiveness in reducing symptom severity and improving recovery rates among these adolescents. The first step of the PRIDE stepped care treatment architecture is a brief, low-intensity problem-solving intervention grounded in stress-coping theory and delivered by lay counsellors. This intervention will be tested against a control arm receiving enhanced “usual care” (essentially no care) of problem-solving booklets without counsellor contact. A stepped-wedge “trial within a trial” will evaluate the effect of school-wide sensitization activities on the number of referrals generated for the PRIDE intervention. The formative research phase and four service pilots are now complete. Service Pilot 5 is currently underway with the RCT launch date set for late August. Our hypothesis is that the PRIDE intervention will be superior to enhanced usual care in reducing the severity of self-reported mental health symptoms and idiographic problems at six weeks post-randomization. The results of this trial may offer a new approach to the treatment of common mental disorders in adolescents that is potentially scalable.