Moving can be detrimental to the development of children from low-income families. Quality public early care and education programs, such as Head Start, may be a possible mechanism to support low-income children living in residentially unstable circumstances. Using data from the Head Start Impact Study (HSIS), we explored whether Head Start participation (via random assignment) moderates how residential mobility is associated with children’s health, cognitive development, and socioemotional functioning prior to school entry among a racially and ethnically diverse sample of 3- and 4-year-old children from low-income families (N = 3419). Results of propensity-score weighted instrumental variable analyses indicated a moderate effect size of Head Start attenuating the adverse link between prior multiple residential moves and parent-reported child health. Future directions for research and policy implications are discussed. (author abstract)