BACKGROUND: Post-traumatic stress symptoms develop in a quarter to half of injured children affecting their longer-term psychologic and physical health. Evidence-based care exists for post-traumatic stress; however, it is not readily available in some communities. We have developed an eHealth program consisting of online, interactive educational modules and telehealth therapist support based in trauma-focused cognitive behavioral therapy, the Reducing Stress after Trauma (ReSeT) program. We hypothesize that children with post-traumatic stress who participate in ReSeT will have fewer symptoms compared to the usual care control group. METHODS: This is a randomized controlled trial to test the effectiveness of the ReSeT intervention in reducing symptoms of post-traumatic stress compared to a usual care control group. One hundred and six children ages 8-17 years, who were admitted to hospital following an injury, with post-traumatic stress symptoms at 4 weeks post-injury, will be recruited and randomized from the four participating trauma centers. The outcomes compared across groups will be post-traumatic stress symptoms at 10 weeks (primary outcome) controlling for baseline symptoms and at 6 months post-randomization (secondary outcome). DISCUSSION: ReSeT is an evidence-based program designed to reduce post-traumatic stress symptoms among injured children using an eHealth platform. Currently, the American College of Surgeons standards suggest that trauma programs identify and treat patients at high risk for mental health needs in the trauma system. If effectiveness is demonstrated, ReSeT could help increase access to evidence-based care for children with post-traumatic stress within the trauma system. TRIAL REGISTRATION: ClinicalTrials.gov NCT04838977. 8 April 2021.