The purpose of this pilot randomized controlled trial (RCT) was to intervene with parents of overweight/obese 4- to 8-year-old children to improve child internalizing and externalizing behaviors. Parent–child dyads (N = 60) were randomly assigned to treatment or comparison conditions. Parents attended four intervention sessions at their child’s primary health care office over 3 months. Child behaviors were assessed at 0, 3, 6, and 12 months post intervention. Parental beliefs in their skills/abilities increased in the experimental group parents, but there was no statistical difference between groups at any time. Child externalizing behaviors significantly decreased from baseline to postintervention for both groups (F = 3.26, p = .020). Post hoc model testing suggests that this change was more pronounced in the intervention group (F = 0.56, p = .692). Child somatic symptoms significantly decreased over time (F = 4.55, p = .004), and there were group differences in child depressive behaviors (F = 6.19, p = .020). These findings suggest that a parent-focused intervention program demonstrated positive preliminary effects on children’s behaviors.