In recent years, policymakers’ and practitioners’ interest in school climate as a contributor to K-12 student learning and classroom processes has increased, both in the US and internationally. However, researchers have not yet examined the influence of school climate on the youngest learners in these contexts — prekindergartners. Using data from the Boston Public Schools, where the public prekindergarten program is housed in elementary schools, we explored associations among dimensions of school climate as reported by teachers and older peers, observed measures of prekindergarten classroom quality, and gains in children’s receptive vocabulary and executive function across the prekindergarten year. Student participants included 299 children attending full-day prekindergarten programs across 35 elementary schools in 61 classrooms. Findings indicated that school emotional climate had small positive association with prekindergarten classroom emotional support. School-level measures of teacher effectiveness also had positive associations with prekindergarten classroom levels of emotional support and classroom organization. School climate dimensions were not associated with children’s receptive vocabulary and executive function gains across the prekindergarten year. Results are discussed in the context of current school climate research and state-wide accountability efforts to assess school quality.