Propensity score matching was used to compare third-grade test scores in English language arts, mathematics, science, and social studies for children who had and had not participated in Georgia's Pre-K 4 years earlier. After matching, each group included 46,262 children (mean age 8.36 years in third grade). In all subject areas, children who had participated in Georgia's Pre-K scored significantly higher (Cohen's D = 0.06 to 0.09), and pre-K participation was associated with an 11% to 17% increase in the odds of scoring proficient or above. Among children enrolled in free or reduced-price lunch, participation in Georgia's Pre-K was associated with higher test scores and greater likelihood of scoring proficient or above; however, the opposite was true for children not enrolled in free or reduced-price lunch. Associations between pre-K participation and math scores were stronger for children whose home language was not English as compared to those whose home language was English.