In 2021, California committed to making transitional kindergarten (TK)--a school-based preschool program initially designed for older 4-year-olds--available for all 4-year-olds by 2025-26. As TK becomes universal, California will need to greatly expand the early learning workforce. This brief provides estimates of how many TK teachers California will need; describes the potential supply pools that could meet this demand; outlines pathways into the profession; and offers recommendations to help stabilize, support, and expand the entire early childhood workforce. [For the full report, see ED622846.]