The current review evaluates the use of treatment fidelity strategies in evidence-based parent training programs for treating externalizing disorders. We used a broad framework for evaluating treatment fidelity developed by the National Institutes of Health Treatment Fidelity Workgroup that includes the aspects of treatment design, treatment delivery, training providers, and assessment of participant receipt of treatment and enactment of treatment skills. Sixty-five articles reporting outcome trials of evidence-based parent training programs met inclusion criteria and were coded for treatment fidelity strategies. The mean adherence to fidelity strategies was .73, which was higher than two previous review studies employing this framework in the health literature. Strategies related to treatment design showed the highest mean adherence (.83), whereas training of providers and enactment of treatment skills had the lowest (.58). In light of an increasing emphasis on effectiveness and dissemination trials, the broader treatment fidelity framework as applied in this review focuses needed attention on areas often overlooked in fidelity practices, such as training providers and generalization of treatment skills. We discuss the strengths and limitations of fidelity practices in parent training studies, implications of these findings, and areas for future research.