Occupational therapists use school-based yoga programs, but these interventions typically lack manualization and evidence from well-designed studies. Using an experimental pretest–posttest control group design, we examined the effectiveness of the Get Ready to Learn (GRTL) classroom yoga program among children with autism spectrum disorders (ASD). The intervention group received the manualized yoga program daily for 16 wk, and the control group engaged in their standard morning routine. We assessed challenging behaviors with standardized measures and behavior coding before and after intervention. We completed a between-groups analysis of variance to assess differences in gain scores on the dependent variables. Students in the GRTL program showed significant decreases (p < .05) in teacher ratings of maladaptive behavior, as measured with the Aberrant Behavior Checklist, compared with the control participants. This study demonstrates that use of daily classroomwide yoga interventions has a significant impact on key classroom behaviors among children with ASD.