This study investigated the causal impact of attending a state-funded pre-K program, the Virginia Preschool Initiative (VPI), on letter name knowledge using a regression discontinuity (RD) design. Children who attended VPI (n = 9,689) had higher letter name knowledge (9 letters higher) compared to students who had just begun VPI (n = 10,897). Findings were robust across various model specifications and imputation methods used. Effect sizes were large (ES = 0.89-1.01) and comparable to other statewide pre-K evaluations using an RD design with a similar outcome. (author abstract)