This research focuses on the associations between interactive processes of early childhood classrooms and gains in children's cognitive self-regulation (CSR) across the preschool year. Data from 803 children (45.8% female; M = 54 months; 39.1% Caucasian, 26.3% African American, 24.6% Hispanic, 9.9% Other) were collected at fall and spring of the preschool year, and classroom observations were conducted three times throughout the year. Multilevel models tested associations between classroom behaviors of teachers and students using the Classroom Observation in Preschool and the Teacher Observation in Preschool and gains children made in a CSR composite score (Dimensional Change Card Sort, Peg Tapping, Head Toes Knees Shoulders, Copy Design, and Corsi Blocks) across the preschool year. After controlling for demographic covariates and children's pretest scores, both affective and cognitive classroom processes were associated with gains. More teacher behavior approving, less disapproving, and more positive emotional tone were associated with gains. The proportion of observed time teachers spent delivering instruction as well as the proportion of time children were involved with mathematics and literacy were also related to CSR gains, as was the quality of teacher instruction. Although exploratory, these results highlight the potential for modifications in classroom practices to aid in children's CSR development.