Background: Despite high rates of mental health problems, including suicide, self-harm, and panic attacks, adolescents do not usually seek help from adults and are more likely to seek help from their peers. To prepare adolescents to support each other, a digital mental health first aid program, called Brain Pilot, was designed for young people.    Objectives: The Brain Pilot program Aims to improve adolescents’ mental health literacy, resilience, and self-efficacy in order to support themselves and their peers. Our study will evaluate the effectiveness of Brain Pilot program in achieving its outcomes, as well as the appropriateness of the program. This evaluation research will also assess the type of support provided by teachers to students who completed the program.   Methods: Using a mixed-methodsapproach, we will analyse pre and post training survey data to measure changes in mental health outcomes among adolescents aged between 15 and 18 in Australia. A focus group with 6-8 program participants (Youth Advisory Group members) and semi-structured interviews with 10 other adolescents will be conducted to explore the key Findings from the surveys. To participate, adolescents will be required to obtain parental consent and provide assent. To understand suitability of the teachers training guide, trained teachers will be surveyed and interviewed.   Discussion: Our study will highlight digital strategies to address youth suicide, self-harm, and panic attacks by improving young people’s capacity in supporting their peers. Our evaluation will also provide insights on co-design with adolescents to ensure appropriate messaging and ongoing support for trained adolescents. Our process evaluation findings will help in informing future implementation of Brain Pilot in Australia and overseas.