BackgroundIn low- and middle-income countries (LMIC), there is a substantial gap in the treatment of mental and behavioral health problems, which is particularly detrimental to adolescents and young adults (AYA). The Common Elements Treatment Approach (CETA) is an evidence-based, flexible, transdiagnostic intervention delivered by lay counselors to address comorbid mental and behavioral health conditions, though its effectiveness has not yet been tested among AYA. This paper describes the protocol for a randomized controlled trial that will test the effectiveness of traditional in-person delivered CETA and a telehealth-adapted version of CETA (T-CETA) in reducing mental and behavioral health problems among AYA in Zambia. Non-inferiority of T-CETA will also be assessed.MethodsThis study is a hybrid type 1 three-arm randomized trial to be conducted in Lusaka, Zambia. Following an apprenticeship model, experienced non-professional counselors in Zambia will be trained as CETA trainers using a remote, technology-delivered training method. The new CETA trainers will subsequently facilitate technology-delivered trainings for a new cohort of counselors recruited from community-based partner organizations throughout Lusaka. AYA with mental and behavioral health problems seeking services at these same organizations will then be identified and randomized to (1) in-person CETA delivery, (2) telehealth-delivered CETA (T-CETA), or (3) treatment as usual (TAU). In the superiority design, CETA and T-CETA will be compared to TAU, and using a non-inferiority design, T-CETA will be compared to CETA, which is already evidence-based in other populations. At baseline, post-treatment (approximately 3–4 months post-baseline), and 6 months post-treatment (approximately 9 months post-baseline), we will assess the primary outcomes such as client trauma symptoms, internalizing symptoms, and externalizing behaviors and secondary outcomes such as client substance use, aggression, violence, and health utility. CETA trainer and counselor competency and cost-effectiveness will also be measured as secondary outcomes. Mixed methods interviews will be conducted with trainers, counselors, and AYA participants to explore the feasibility, acceptability, and sustainability of technology-delivered training and T-CETA provision in the Zambian context.DiscussionAdolescents and young adults in LMIC are a priority population for the treatment of mental and behavioral health problems. Technology-delivered approaches to training and intervention delivery can expand the reach of evidence-based interventions. If found effective, CETA and T-CETA would help address a major barrier to the scale-up and sustainability of mental and behavioral treatments among AYA in LMIC.Trial registrationClinicalTrials.govNCT03458039. Prospectively registered on May 10, 2021