This paper exploits variation resulting from a series of federal and state Medicaid expansions between 1979 and 2014 to estimate the effects of children’s access to public health insurance on the labor market outcomes of parents. The results imply that the extended Medicaid eligibility of children leads to positive parental labor supply responses at the extensive and intensive margins. The analysis of mechanisms suggests that Medicaid is less likely to work through marital and educational outcomes and that the effects are driven by the head of the family. The findings also illustrate the importance of siblings’ spillovers of Medicaid eligibility for program take-up of children and parental outcomes.