Objective: There are currently no empirically-supported, comprehensive school-based interventions (CSBIs) for children with autism spectrum disorder (ASD) without concomitant intellectual and language disability. This study compared outcomes for a CSBI (schoolMAX) to typical educational programming (services-as-usual [SAU]) for these children. Method: A total of 103 children (ages 6-12 years) with ASD (without intellectual and language disability) were randomly assigned by school buildings (clusters) to receive the CSBI (n=52 completed) or SAU (n=50 completed). The CSBI was implemented by trained school personnel and targeted social competence and ASD symptoms using social skills groups, emotion recognition instruction, therapeutic activities, behavioral reinforcement, and parent training. Outcome measures tested the effects of the CSBI on social competence and ASD symptoms, as well as potential collateral effects on academic achievement. Outcomes (baseline-to-follow-up) were assessed using tests of social-cognition and academic skills and behavioral observations (by masked evaluators) and parent-teacher ratings of ASD symptoms and social/social-communication skills (non-masked) [ClinicalTrials.gov, NCT03338530, https://www.clinicaltrials.gov/]. Results: The CSBI group improved significantly more than the SAU group on the test of emotion recognition skills and parent-teacher ratings of ASD symptoms (primary outcomes) and social/social-communication skills (secondary outcome). No differences between groups were detected for recess social interactions or academic skills. Conclusions: The CSBI improved several core areas of functioning for children with ASD compared to usual educational programming. Additional intervention elements may be needed to expand the efficacy of the CSBI so that the observed skills/symptom improvements generalize to recess social interactions and/or academic skills are enhanced. [This paper was published in the "Journal of Clinical Child and Adolescent Psychology" v48 n6 p922-933 Dec 2019.]