PURPOSE: This study examined the cost-effectiveness of standard parent-child interaction therapy (PCIT) and three adaptations: intensive-PCIT (I-PCIT), small group PCIT, and large group PCIT. METHODS: This study used cost-effectiveness analyses to calculate average cost-effectiveness ratios, which represents the average cost for one family to change one standard deviation on each outcome measure: externalizing behavior problems, positive parenting skills, negative parenting skills, child compliance, and parenting stress. RESULTS: While it had the lowest initial set up cost, results indicated that standard PCIT was the least cost-effective option in reducing child disruptive behaviors and in increasing child compliance. Large group PCIT was the most cost-effective in increasing positive parenting skills and child compliance and in reducing negative parenting skills and parenting stress. I-PCIT was the most cost-effective in reducing child disruptive behaviors and the second most cost-effective option in increasing positive parenting skills and child compliance and in decreasing negative parenting. CONCLUSIONS: As large group and I-PCIT were the most cost-effective in different domains, both could be recommended to parents as treatment options. Future research should confirm our cost-effective results within community settings.