Experiencing large differences between pre-k and kindergarten classroom contexts may affect children’s academic development as they start school. This study examined differences between classroom contexts in pre-k and kindergarten (teacher-child interactions, time on academic content, and academic rigor) and associations with literacy, language, and math achievement in kindergarten fall and spring. 1498 children were followed from public pre-k through kindergarten (mean age = 52.8 months old at the start of pre-k, SD = 3.5). Children were ethnically and linguistically diverse (White = 7%, Black = 20%, Hispanic = 61%, Other = 12%; English at home = 21%, Spanish at home = 55%; other language at home = 24%). Piecewise growth modeling showed that experiencing a decrease in the quality of interactions or an increase in time on content or academic rigor was associated with lower than expected achievement in the fall of kindergarten but greater gains across the kindergarten year. (author abstract)