The goal of the present study was to examine the contribution of executive function (EF) and social cognition to individual differences in emotion regulation (ER) in preschool children. Sixty 3-, 4-, and 5-year-old children were administered a battery of EF tasks, two theory of mind tasks, a measure of verbal ability, and an ER task. In addition, parents completed the Behavior Rating Inventory of Executive Functioning—Preschool Version (BRIEF-P). Performance on the theory of mind tasks as well as parental ratings of executive function was not related to performance on the ER task. However, a component of EF (i.e., inhibition) approached significance with children's displays of positive behaviors during the ER task. Verbal ability was related to the regulation of positive but not negative emotions. Parental ratings of shifting accounted for a significant amount of variance in parental ratings of ER, even after controlling for verbal ability. The findings are discussed in the context of different conceptualizations of the developmental relation between ER and EF.