In Uganda, religion and education had long been inextricably linked, with education being primarily in the hands of Protestant and Catholic Christians until 1925. Gradually, the government began to take control of education, and after independence, the close relationship between education and religion was separated after the Castle Commission report in 1963. Secondary education then expanded in the 1980s, overcoming economic difficulties and political turmoil. From the perspective of institutional history, government intervention resulted in expanding secondary education, but how were schools actually established and who was responsible for this? Therefore, this paper focuses on the process of establishing a missionary secondary school in Kassanda District, Uganda, which was established in the 1980s, and aims to clarify how local religious organizations were involved in the establishment of the school. This paper first provides an overview of how school education has developed in Uganda in relation to the activities of missionaries. Next, the establishment process of the missionary A Secondary School in Kassanda District, Uganda, is described based on the School Profile, interviews with those who funded the establishment, and additional interviews conducted. Finally, some reflections are given on the role of missionary work in Ugandan education and how the connection between school and Christianity is carried over to the present day. By looking at the actual process of establishing schools, this paper reveals the contribution of community Christians to the establishment of schools and the strong connections that continue to the present day, which cannot be seen from the macro perspective of institutional history.