Children with disruptive behavior disorders (DBDs) experience high rates of comorbid psychopathology, including internalizing disorders. According to the dual pathway model, comorbid internalizing symptoms may be associated with less (buffer hypothesis) or more (multiple problems) severe clinical presentations among children with DBDs. We examined whether the presence of comorbid internalizing symptoms is associated with differences in the severity of clinic-referred children’s (N???=???284, age 6 to 12) disruptive behavior, as measured by parent ratings of their oppositionality-defiance, impairment, and callous-unemotional traits. Potential gender effects were also examined. Children with DBD and clinically elevated internalizing symptoms showed significantly higher levels of oppositionality-defiance and overall behavioral impairment and, unexpectedly, callous-unemotional traits, than children with DBD and sub-clinical internalizing symptoms. There were no significant main effects of gender or interactions between internalizing symptoms and gender. Results are consistent with the multiple problems hypothesis and suggest that children with DBDs should be assessed for internalizing symptoms. Moreover, children with comorbid DBD and internalizing disorders may require specific clinical attention, such as sequenced or modular interventions, or interventions targeting relevant transdiagnostic processes, in order to meet their treatment needs.