California is on the cusp of implementing universal preschool—a step that could help level the playing field for young children. Over the next few years, all four-year-olds will become eligible for Transitional Kindergarten (TK), which has been part of the state’s early learning programs since 2012. To help prepare for an equitable expansion, we provide a demographic portrait of TK students and the districts and schools offering TK, highlighting existing gaps in participation and access. (author abstract)