Transition to school is one of the most important processes experienced by children and their families. In keeping with ecological models of child development, a broad spectrum of factors is postulated to impact children’s adjustment to school. In this chapter, the biological basis of early development as it impacts school adjustment is briefly reviewed, and a holistic, developmental concept of school readiness is introduced. A comparison of factors influencing school readiness between Canada and Mexico shows the consistent impact of socio-economic characteristics, family, and gender. Further, parents are considered the main agents in creating a unique early environment that fosters development of learning and social skills. Empirical studies investigating parent engagement in child’s home-based, and community-based activities show that these activities contribute to kindergarten outcomes in all areas of school readiness. Transition to school can be improved through family involvement in organized community-based activities that are not focused on the skills traditionally considered relevant for school success. These findings are considered to emphasize that, first, transition to school is a process encompassing many areas of child development; and second, a collaborative approach between families, schools, and communities is the one most likely to lead to improvement in children’s experience of transition and a successful school adjustment.