Immigration enforcement has intensified in the United States, but there is little evidence on its effect on U.S.†born individuals’ labor outcomes. Exploiting the staggered rollout of a large, federal enforcement policy—Secure Communities (SC)—across local areas, we estimate a difference-in-differences model with time and location fixed effects. We find that SC reduced the labor supply of college†educated U.S.†born mothers with young children. If SC exposure occurred when children are below age three, the negative effects on labor supply persist over time. We further show increased cost of outsourcing household production, due to reduced undocumented immigrants’ labor supply, is an important mechanism.