This study examines the influence of nonresident fathers' formal and informal cash child support on children's cognitive skills and behavior at 5 years of age. Taking advantage of the panel structure of the Fragile Families and Child Wellbeing Study, the analyses control for child outcomes at age 3, as well as for a variety of child and family sociodemographic and psychosocial characteristics. Findings suggest that fathers' provision of informal cash support (but not formal support), particularly at or above the median amount, is positively associated with children's cognitive scores. Findings also suggest that provision of formal child support is adversely associated with internalizing and aggressive behaviors. Potential explanations and implications of these results for policy and future research are discussed.