Choe Sejin (1473–1542) was a Korean linguist, educator, and a proponent of hangul during the Joseon Dynasty. He is of the Goesan Choe clan and courtesy name was Gongseo (공서; 公瑞). Choe was an official interpreter in the Korean embassies in Beijing, and so he also made extensive documentation of the colloquial Chinese at the time.
Choe devised the modern South Korean order of the hangul letters, and assigned names to the letters. His most famous book on hangul is the Hunmong Jahoe (훈몽자회; 訓蒙字會 "Collection of Characters for Training the Unenlightened (= Kids)", 1527).