The work of the Australian mission in the southern part of Korea during the first half of the twentieth century has been a relatively undeveloped subject in scholarly research. By focusing on the educational work of the mission between 1910 and 1941, this article provides an overview of how the missionaries interacted with the Japanese colonial authority and the Korean people. The purpose of this article is twofold. First, it traces how the missionary work in South Gyeongsang Province evolved in terms of education. Second, it identifies the process by which mission education and Japanese educational policy interacted, focusing on the two secondary schools of the mission: the D.M. Lyall Memorial School and the J.B. Harper Memorial School. Mission education during this period had three different implications: religion, modernity and politics. For the missionaries, education was intended to spread Christianity; for the Koreans, the mission schools provided opportunities for modern learning; for the Japanese authorities, schooling was considered a vehicle for political socialisation. The educational work of the Australian mission shows how the agendas of the missionaries, the Koreans and the Japanese colonial authority intersected and conflicted. Although the Australian mission comprised a smaller group of missionaries who worked exclusively in the southern part of the country, their records are significant. This case study provides a basis for a further comparative analysis within the larger context of colonial Korea.