Research with parents on managing child problem behavior typically measures either child or parent behavior. This study was designed to evaluate the effectiveness of training parents to implement a function-based behavior intervention plan (BIP) in a non-trained natural environment utilizing a Multiple Probe Design across Participants. Participants included four parent-child dyads. Measurement variables included parents' use of effective and ineffective strategies and child problem behavior. Intervention involved training parents to understand and implement the BIP using effective strategies, modeling the effective procedures, and providing feedback following parent implementation of procedures. Results showed that the intervention was very effective in promoting skill generalization of parents and decreasing child problem behavior. The findings have implications for research and clinical practice.