Students with emotional dysregulation are not equipped with the ability to manage their own behavior. This often leads to major disruptions in the general education setting, interfering with the student's learning and the learning of others. This study examined the effects of a mindfulness-based intervention on the presence of disruptive behavior in children with autism spectrum disorder or developmental delays in early elementary inclusion classrooms. An ABAB single-case research design was conducted on four students with characteristics of autism spectrum disorder between the ages of 5 and 8 to determine the effects of a mindfulness-based intervention on their disruptive behavior patterns. The researcher developed a mindfulness-based intervention comprised of structured breathing, mindful movement activities, and statements of positive affirmation for use during this 6-week study. Results of participation in a mindfulness-based intervention suggest an overall positive effect with mixed results on the rate of disruptive behavior. Limitations and future directions are discussed.