The effects of 14 weeks of Kata techniques training on stereotypic behaviors of children with autism spectrum disorders (ASD) were investigated. The study included 30 eligible (diagnosed ASD, school age) children with ages ranging from 5 to 16 years whom they assigned to an exercise (n = 15) or a no-exercise control group (n = 15). Participants of the exercise group received Kata techniques instruction four times per week for 14 weeks (56 sessions). Stereotypy was assessed at baseline (pre-intervention), week 14 (post-intervention), and at one month follow up in both groups. Results showed that Kata techniques training significantly reduced stereotypy in the exercise group. Following participation in Kata techniques training, stereotypy decreased from baseline levels by a M of 42.54% across participants. Interestingly, after 30 days of no practice, stereotypy in the exercise group remained significantly decreased compared to pre-intervention time. The participants of the control group did not show significant changes in the stereotypy. Teaching martial arts techniques to children with ASD for a long period of time consistently decreased their stereotypic behaviors. (Contains 2 figures and 4 tables.)