Read It Again (RIA) is a curriculum for pre-kindergarten (pre-K) classrooms that targets children's development of language and literacy skills. A cluster randomized trial was conducted in which 104 pre-K classrooms in the Appalachian region of the United States were randomly assigned to one of three study conditions: Control (n = 30), RIA only (n = 35), or RIA with expanded professional development components (n = 39). This study tested the impacts of RIA on six measures of children's (n = 506) language and literacy development. There was a significant positive impact of RIA on print concepts, and the impacts of RIA on print knowledge and alphabet knowledge were significantly stronger in classrooms with lower-quality literacy instruction. There were no impacts of RIA on children's language development and no impacts of the professional development components. Implications of the findings for implementing scalable, effective strategies to improve key school readiness outcomes for children from economically-disadvantaged backgrounds are discussed.