While externalizing behaviors are common among children with autism spectrum disorder (ASD), there is a shortage of specialist community-based clinicians to provide treatment. Parent-Child Interaction Therapy (PCIT), an intervention designed to reduce child disruptive behaviors, may be effective for families of children with ASD but has rarely been studied outside of university-based research settings. We examined the effectiveness of PCIT delivered for children with (N = 109) and without (N = 2,324) ASD/developmental delays (DD) across community-based agencies in Oregon. Findings revealed significant reductions in disruptive behavior and positive changes in the parent-child relationship in both groups. These findings support PCIT as an efficacious intervention for children with ASD/DD and demonstrate PCIT's promise in community-based agencies with non-specialized clinicians.