PURPOSE: This study examined the extent to which teacher responsivity education affected preschoolers' language and literacy development over an academic year. Additional aims were to determine whether children's initial language abilities and teachers' use of responsivity strategies were associated with language outcomes, in particular. METHOD: In this randomized controlled trial, preschool centers were assigned to a responsivity education intervention (n = 19 centers, 25 teachers, and 174 children) or a "business-as-usual" control condition (n = 19 centers, 24 teachers, and 156 children). Teachers within the intervention centers received training focused on a set of strategies designed to promote children's engagement and participation in extended conversational interactions across the school day. RESULTS: Hierarchical linear models showed no main effects on children's language skills, although moderating effects were observed such that the intervention appeared to have positive effects for children with relatively high initial language abilities. In addition, teacher use of responsivity strategies was positively associated with vocabulary development. With regard to children's literacy skills, there was a significant main effect of the intervention on print-concept knowledge. CONCLUSIONS: Although teacher responsivity education is viewed as benefitting children's language and literacy development, the impacts of this type of intervention on children's skills warrant further investigation.