The present study tested the impact of a parent behavior-management intervention on child depressive and internalizing symptoms. One hundred eighty-one children were randomly assigned to receive a videotape modeling parenting intervention, the Incredible Years, or to a wait-list control group. Children who received the intervention were more likely to have lower mother-rated mood and internalizing symptoms at post-treatment, compared with children in a wait-list control group. The effect sizes observed in the present intervention fell in the small-to-medium range for the sample as a whole, and some evidence supported the authors' hypothesis that effects would be strongest for children with baseline internalizing symptoms in the clinical range. Subsequent analyses also revealed that perceived changes in parenting effectiveness mediated the effect of treatment on children's post-treatment internalizing symptoms. The finding was consistent with study hypotheses and social learning explanations of child internalizing symptoms that guided selection of putative mechanisms. Implications for counseling psychologists and for designing interventions and prevention strategies for children with internalizing symptoms are discussed. (Contains 3 tables and 1 figure.)