BackgroundInsomnia symptoms may be an important etiological factor for substance use disorders; however, whether improving sleep leads to reductions in problematic substance use among at-risk populations remains unclear. MethodAs such, the current pilot study used a randomized controlled design to test the effects of Brief Behavioral Treatment for Insomnia (BBTI) against a waitlist control among a sample of trauma-exposed young adults with elevated insomnia symptoms who regularly use cannabis (N = 56). Results: Intent-to-treat multilevel modeling analyses indicated that BBTI may be more efficacious than waitlist control in reducing self-reported insomnia symptoms, with large effects three months post-treatment (d = 1.34). Further, our initial evidence suggested that BBTI resulted in reductions in cannabis-related problems with medium to large effects at three months post-treatment (d = 0.75). The current pilot analyses indicated BBTI also reduced cravings to use cannabis to reduce negative emotions in response to trauma cues with a large effect size. ConclusionThis pilot study suggests BBTI may be efficacious not only in improving insomnia symptoms among cannabis users but also in reducing cannabis-related problems and cravings over three months. Future research should replicate these results in a larger, fully powered sample with improved follow-up rates designed to test temporal mediation using multimethod assessments of insomnia symptoms and problematic cannabis use. Overall, BBTI may be a promising intervention for trauma-exposed cannabis users to improve sleep and reduce cannabis-related problems.