Pennsylvania Pre-K Counts (PA PKC) is a state-funded prekindergarten program for 3- and 4-year-old children to help them gain school readiness skills. The goal of PA PKC is to help reduce educational disparities by providing high quality prekindergarten for children who lack opportunities or reside in environments that place them at risk of school failure. This Implementation Study was designed to examine local variations in the statewide implementation of PA PKC in relation to the program regulations and early learning standards. The study entailed surveys with three groups of families (current PA PKC families, former PA PKC families in kindergarten, comparison families in kindergarten), surveys and interviews with PA PKC administrators, and PA PKC administrative data. This process evaluation focused on issues related to the extent of variability in implementation of PA PKC, effectiveness of family engagement, adequacy of supports for continuous quality improvement, and implementation challenges in supporting children's school readiness. The Implementation Study addressed four primary questions: (1) How much local variation exists in the implementation of PA PKC program regulations and standards?; (2) As key stakeholders, how effectively are families engaged in and supported by PA PKC? How does PA PKC view their role in supporting family engagement?; (3) To what extent is adequate support provided by local PA PKC programs and by the Office of Child Development and Early Learning (OCDEL) for continuous quality improvement?; and (4) To what extent are key factors (geographic region and urbanicity/rurality, program size, percent 3-year-olds, provider type, teacher credentials) associated with greater or lesser implementation challenges? What are recommended suggestions for improvement? [This report was prepared by the University of North Carolina at Chapel Hill, School of Education. Additional funding was provided by the BUILD Foundation.]