This study examines the relationship between the Korean Language Institute (KLI), established at Yonsei University after 1959, and the Korea Inter-Mission Language Committee (KIMLC), which represented the Protestant missions in Korea at the time. The existence of the KIMLC and its relationship with the KLI had not been reported until now. The evidence for this study is primarily found in records collected from the archives of the Presbyterian Historical Society. These records indicate that the KIMLC was the successor to the Yonsei Language School Consultation Committee, which was responsible for establishment of the Korean Language Institute at Yonsei University and qualified as the official agent for Korean language learning for missionaries. Futhermore, I discovered that KIMLC was actively involved with KLI through the mid-1960s, advising, participating in, and auditing KLI's Korean language programs. Moreover, from the late 1960s onward, as KLI expanded its language education programs, the KIMLC's role in teaching Korean to missionaries diminished, thus allowing KLI to develop into a more independent institution.