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. 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. 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. 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.