This article uses longitudinal data from approximately 2,000 low-income families participating in the national evaluation of the Comprehensive Child Development Program to examine the associations between preschool children’s living arrangements and their cognitive achievement and emotional adjustment. The analysis distinguishes families in which children live only with their mothers from children who live in biological father, blended, and multigenerational households. Linkages are examined separately for White, Black, and Latino children. Fixed effects regression techniques reveal few significant associations between living arrangements and child development. These findings suggest that substantial diversity exists in the developmental contexts among children living in the same family structure. Policies seeking to change the living arrangements of low-income children may do little to improve child well-being.