The aim of this paper is to point out the specifics of introducing a religious education in Serbia between the two world wars. The period is divided into three sections in which challenges and efforts of the country are seen in terms of unification. Besides, there are great church efforts to introduce and keep as well the Orthodox church religious education at all educational levels. In the first section we are focused on the position of religious education in the Kingdom of Serbia before the unification. Furthermore, we discuss how the church changed its position in the new formed country. The second section explains how conflicts between the “liberal” and “clerical” forces increased in the society, in the case of regulation of education. The third part is focused on the period between 1929 and the final unification of educational policy in the Kingdom of Yugoslavia.