This paper evaluates the effect of Paid Family Leave (PFL) on breastfeeding, which we identify using California’s enactment of a 2004 PFL policy that ensured mothers up to six weeks of leave at a 55 percent wage replacement rate. We employ synthetic control models for a large, representative sample of over 270,000 children born between 2000 and 2012 drawn from the restricted-use versions of the 2003 – 2014 National Immunization Surveys. Our estimates indicate that PFL increases the overall duration of breastfeeding by nearly 18 days, and the likelihood of breastfeeding for at least six months by 5 percentage points. We find substantially larger effects of PFL on breastfeeding duration for some disadvantaged mothers.