The newly-revised California Infant–Toddler Learning and Development Foundations (ITLDF) describe the development infants and toddlers often attain during the birth-to-three age period. This second edition of the ITLDF was developed with input from a broad range of interest holders, researchers, and early learning/education providers, and has been aligned with the California Preschool Transitional Kindergarten Learning Foundations (PTKLF).