To examine child factors and parental characteristics as predictors of discrepancies between parents’ ratings of externalizing and internalizing behavior problems in a sample of preschool children with ADHD and behavior problems and in a nonclinical sample. We investigated correspondence and discrepancies between parents’ ratings on the externalizing and internalizing behavior problems broadband scales of the Child Behavior Checklist version for preschool children (CBCL/1.5–5). Parents of 152 preschool children, with ADHD and behavior problems (n = 72) and nonclinical children (n = 80), aged between 28 and 72 months (M = 47.26, SD = 12.7), completed the CBCL/1.5–5. Candidate predictors of discrepancy included the child’s age and sex, and parents’ levels of parenting stress, depressive mood, attention-deficit and disruptive behavior. Hierarchical multiple regression analyses were conducted. Correspondence between parents, both for ratings on internalizing and externalizing behavior problems, was high (r = .63–.77). In the clinical sample, mothers rated the severity of externalizing behavior problems significantly higher than did fathers (p =