A communication disorder (CD) is an impairment in the ability to receive, send, process, and comprehend concepts or verbal, nonverbal, and graphic symbol systems. An estimated 40 million Americans have CD, and among children aged 3 - 17, nearly 10% of them have some sort of CD. What is the impact of CD in the classroom? Are children who have CD more disruptive than typically developing children? To answer these questions, I located 12 scientific studies that compared children with CD to typically developi ng children. Data from each study was used to compute the effect size, and the overall weighted average effect size was d = 0. 43 , which is a medium effect. An implication of this finding is that teachers need special training in how to control children w ith CD so that they have a positive learning experience.