A startling 20 to 50 percent of children in the United States are impacted by violence, either as victims or as witnesses. Many of these children suffer numerous deleterious outcomes that include post-traumatic stress symptoms, depression, and poor school performance. Despite the deleterious impact on children, there is a paucity of research concerning “what works” in terms of school-based interventions. The current study evaluated the effectiveness of CBITS under two conditions: early-intervention and late-intervention. The CBITS program consists of 10 group sessions that include relaxation training, real-life problem-solving, dealing with anxiety-provoking situations, and counseling on coping with the violent event. A total of 126 students eligible to participate in the CBITS program were randomly assigned to either the early-intervention group or the late-intervention group. Participants completed baseline assessments, as well as 3- and 6-month follow-up assessments. Results indicated that both the early-intervention and late-intervention participants substantially improved with regard to post-traumatic stress symptoms as a result of the program. The implementation of the program was successfully carried out by program staff and was delivered with high quality. Further evaluations should assess the impact of the program over an extended follow-up period. Figures