Reciprocal associations among measures of family resources, parenting quality, and child cognitive performance were investigated in an ethnically diverse, low-income sample of 2,089 children and families. Family resources and parenting quality uniquely contributed to children's cognitive performance at 14, 24, and 36 months, and parenting quality mediated the effects of family resources on children's performance at all ages. Parenting quality continued to relate to children's cognitive performance at 24 and 36 months after controlling for earlier measures of parenting quality, family resources, and child performance. Similarly, children's early cognitive performance related to later parenting quality above other measures in the model. Findings merge economic and developmental theories by highlighting reciprocal influences among children's performance, parenting, and family resources over time.