The present study evaluated the effectiveness of a mixed martial arts (MMA) intervention in improving executive functions (EFs) in a sample with autism spectrum disorder (ASD). School-aged children with ASD were randomly assigned to a MMA intervention group or a waitlist control (WLC) group. The intervention featured a 26-class program over a 13-week period; the WLC group did not participate in any martial arts between pre- and post-test. Results indicated that the MMA group had significantly better EFs at post-test compared to the WLC group. The intervention appeared to be efficacious in meeting its goals of improving the executive functioning of children with ASD. The present study extends the current literature on the malleability of EFs among children with ASD.