We study the effect of Protestantism on human capital acquisition using novel data on 234 counties and 2,478 towns in the Korean peninsula in 1930. First, we show that towns with a larger number of native Protestant churches have higher literacy rates throughout colonial Korea. To establish causality, we employ hand-collected data on the exposure to foreign Protestant missionaries as an instrumental variable for the number of native Protestant churches. Furthermore, we study the differential success of different missionary societies, using a spatial RDD that exploits the Comity Agreement of 1909 which geographically divided Korea between missionary societies. We show that Presbyterians, who put more emphasis on empowering local churches, were more successful at attracting members, and fostering literacy, than the Methodists with their more hierarchical structure.