This study examined mothers’ ability to accurately predict their sons’ performance on executive functioning tasks in relation to the child’s behavior problems. One-hundred thirteen mothers and their 4–7 year old sons participated. From behind a one-way mirror, mothers watched their sons perform tasks assessing inhibition and planning skills. Before each task, mothers predicted how their sons would perform. Both the absolute discrepancy between mothers’ predictions and their child’s performance (summing both mothers’ over- and under-estimations), and the mothers’ under-estimations of their child’s performance accounted for significant variance in reports of child behavior problems. These predictions were significant even with the child’s age and level of task performance controlled. The results suggest that a mother’s lack of ability to accurately predict her child’s executive functioning skills may contribute to the development of child problems, perhaps through increased difficulties in parenting in a manner that is responsive to the child’s abilities.