A number of factors contribute to the school readiness of children, including child and family characteristics, neighborhood residence, and early care and education experiences. Early skills are the foundation for later school and life success. The current study examines the influence of school composition, classroom quality, and teacher preparation on kindergarten children's school readiness using data originally collected as part of an evaluation of a school readiness intervention. Children's academic school readiness was predicted by teachers' preparation in child development. Children had fewer problem behaviors when their teachers were more highly educated and specialized in child development and, surprisingly, when they attended schools with higher concentrations of low-income students. Child race was the only variable significantly related to children's social skills. These results suggest that teachers play an important role in children's development of foundational skills, and provide support for specific and targeted professional development around early childhood education.