The purpose of the article: to analyze the movement for the Ukrainianization of the autocephalous «Orthodox Church in Poland» in Volyn. The research methodology is grounded on the principles developed by the “Annals” school, in particular, objectivity in judgments about the past, the desire to understand the mentality of social groups of that time, first of all the clergy, the specifics of their relationships. In the process of research, the methods of analysis and synthesis, as well as chronological, comparative and descriptive methods were applied.The scientific novelty of the obtained results consist in the deepening of the understanding of the national identification of the clergy and believers in Volyn, the evolution of the Ukrainian church movement in Poland in the 20’s and 30’s of the 20th century in Volyn, based on the archival and published sources. Conclusions. In the conditions of Polish statehood, the clergy of the Orthodox Volyn Diocese developed in the direction of national self-identification. During this period, the intellectual level of the priests grew, as did their desire for the Ukrainization of their own church. In Volyn, the idea of Ukrainization of the Orthodox Church had support among believers, the public, and most importantly, the clergy and hierarchy, who actively implemented it. Therefore, Volyn appears as a center where the Ukrainian church movement is born and begins to strengthen. It was distinguished by the growth of national consciousness of Ukrainians and significant achievements in the Ukrainianization of the Orthodox Church in Volyn, which was part of the Orthodox Church in Poland. The movement for Ukrainization was aimed at conducting liturgies and church administration in the Ukrainian language, teaching religion in schools in the Ukrainian language, translating liturgical literature into the Ukrainian language, consecrating Ukrainian bishops, separating all Ukrainian parishes into a separate diocese headed by a Ukrainian bishop, etc. The Ukrainian church movement in Volyn helped preserve the identity of the Ukrainian people in the conditions of Polish statehood.