The Incredible Years (IY) Series includes separate group interventions to improve parenting interactions, teacher classroom management, and child social-emotional regulation. Although originally developed to treat early onset conduct problems, IY targets many of the proposed mechanisms and risk factors for internalizing distress in early childhood. Prior studies have demonstrated the effects of the IY parent intervention on co-occurring depressive symptoms. We attempted to extend these findings by examining the unique and combined effects of IY interventions on children's co-occurring internalizing symptoms. One-hundred and fifty-nine families with children ages 4- to 8-years-old were randomly assigned to parent training (PT); parent plus teacher training (PT + TT); child training (CT); child plus teacher training (CT + TT); parent, child, plus teacher training (PT + CT + TT); or a waiting list control group. Children who received any of the intervention components were more likely to have lower mother-rated internalizing symptoms at posttreatment compared to children in a wait-list control group. Implications for future research and for designing interventions and prevention strategies for children with internalizing symptoms are discussed. (Contains 2 tables.)