Evidence-supported parenting interventions (ESPIs) increasingly are used in child welfare to improve child well-being and parenting. However, little evidence exists on the effectiveness of ESPIs with biological families of children in foster care with serious behavioral health problems. To address this gap in the literature, we examined the outcomes of in-home Parent Management Training Oregon model (PMTO). PMTO was evaluated in a randomized trial in which 918 children were assigned to PMTO or services as usual with assessment at baseline, 6 months, and 12 months. Outcome domains included child social-emotional well-being, parenting, and caregiver functioning. Our results show PMTO demonstrated linear improvements in children's social-emotional functioning, problem behaviors, and social skills. Although results for parenting were inconclusive, two of four caregiver functioning outcomes (parent mental health and readiness for reunification) were significantly improved. Overall, these findings suggest PMTO and similar ESPIs may hold promise for promoting better outcomes for biological families of children in foster care with behavioral health problems.