Behavioral parenting programs are a theory-driven and evidence-based approach for reducing disruptive child behavior. Although these programs are effective on average, they are not equally effective in all families. Decades of moderation research has yielded very few consistent moderators, and we therefore still have little knowledge of who benefits from these programs and little understanding why some families benefit more than others. This study applied a baseline target moderation model to a parenting program, by (1) identifying parenting profiles at baseline, (2) exploring their correlations with other family characteristics and their stability, and (3) assessing whether they moderate intervention effects on child behavior. Individual participant data from four Dutch studies on the Incredible Years (IY) parenting program were used (N = 785 caregiver–child dyads). Children (58.2% boys) were at risk of disruptive behavior problems and aged between 2 and 11 years of age (M = 5.85 years; SD = 1.59). Latent profile analyses indicated three distinct baseline parenting profiles, which we labeled as follows: Low Involvement (81.4%), High Involvement (8.4%), and Harsh Parenting (10.1%). The profiles caregivers were allocated to were associated with their education, minority status, being a single caregiver, and the severity of disruptive child behavior. We found neither evidence that baseline parenting profiles changed due to participation in IY nor evidence that the profiles predicted program effects on child behavior. Our findings do not support the baseline target moderation hypothesis but raise new questions on how parenting programs may work similarly or differently for different families.