We report on parent outcomes from a randomized clinical trial of parent training (PT) versus psychoeducation (PEP) in 180 children with autism spectrum disorder (ASD) and disruptive behavior. We compare the impact of PT and PEP on parent outcomes: Parenting Stress Index (PSI), Parent Sense of Competence (PSOC), and Caregiver Strain Questionnaire (CGSQ). Mixed-effects linear models evaluated differences at weeks 12 and 24, controlling for baseline scores. Parents in PT reported greater improvement than PEP on the PSOC (ES = 0.34), CGSQ (ES = 0.50), and difficult child subdomain of the PSI (ES = 0.44). This is the largest trial assessing PT in ASD on parent outcomes. PT reduces disruptive behavior in children, and improves parental competence while reducing parental stress and parental strain.