Within-family associations between changes in income and changes in the home environment during infancy and early childhood were examined using data from the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development (n = 1364). Linear and nonlinear (i.e., semilog) specifications were estimated for family income. In addition, variations in income effects were estimated as a function of the level of developmentally stimulating resources in homes during early infancy. Increases in family income were positively associated with increases in the quality of children's home environments. The estimated effects of income were largest for families who had low incomes and low-quality early home environments. These results were evident for physical characteristics of the home that likely required monetary investments, as well as for psychosocial characteristics of the home.