Background: Children involved with the child welfare system are a vulnerable population and are often exposed to multiple adversities. Indeed, children living in homes characterized by abuse and neglect may also be at risk of exposure to other forms of family violence, such as intimate partner violence (IPV). For example, a growing literature shows that child maltreatment and IPV co-occur at rates between 30%-60%. Exposure to co-occurring forms of family violence may place children at increased risk for poor behavioral health outcomes, but less is known regarding the specific forms of child maltreatment and IPV that co-occur and whether their co-occurrence differentially impacts children’s externalizing behaviors. Therefore, this study examined the different forms of family violence that co-occur and their relationship to children’s externalizing behaviors across developmental stages. Method: Longitudinal data of caregiver reports (N = 2,232) of parenting behaviors, experiences of intimate partner violence, and children’s externalizing behaviors from the National Survey of Child and Adolescent Well-being II (NSCAW-II) were used. A mixture modeling approach was employed in which latent class models estimated subgroups of children (preschool-age and school-age) who experienced co-occurring family violence and regression models estimated which subgroups of children were at risk of externalizing behavior problems. Results: Three latent classes were identified: (1) high family violence; (2) situational couple violence and maltreatment; and (3) maltreatment-only. Preschool-aged children classified into the situational couple violence and maltreatment class were more likely to exhibit greater externalizing behavior problems (b = 3.73, p <.05) than children classified into the maltreatment-only class. No significant differences between classes and children’s externalizing behavior problems were found for school-aged children. Conclusion: This study highlights the importance of using diverse approaches to quantify and synthesize different forms of family violence that may co-occur. The distinct classes of family violence and their differential impact on children’s behavior suggests a need for robust screening as well as a strong prevention and intervention response to address children’s dual maltreatment and IPV exposure. Findings may additionally inform shared parenting approaches in the context of family violence.