The article highlights the educational, social and cultural activities of Vasyl Ilnytskyi, the famous Ukrainian Galician teacher, cultural and educational leader, historian, and priest in the second half of the nineteenth century. The author analyzes the stages of his development as a gymnasium teacher, the formation of his personality as a leader of a new generation of Ukrainian Galician intelligentsia (advocating actively the rights of the Ukrainian language, introducing it into the educational process of primary and secondary schools, participating in the organization and activities of a number of cultural and educational institutions, etc.). The paper emphasizes V. Ilnytskyiʼs merits for the development of gymnasium education in Galicia. It reveals the aspects of his teaching and management activities in Stanislav and Ternopil state gymnasiums. The focus is laid on his work for many years at the Lviv Academic Gymnasium, which he headed for more than a quarter of his life (1867–1893). It was due to his direct involvement that the process of the Ukrainization of this, the only state gymnasium in Austria-Hungary at that time with the Ukrainian language of instruction, was completed. In 1868, V. Ilnytskyi initiated the creation of a separate government commission for the preparation of Ukrainian language educational literature that in a short time with the support of the well-known practicing teachers Yu. Romanchuk, A. Vakhnyanyn, and others managed to make significant progress in solving this important national issue: the translations of foreign language textbooks were made and a number of native-language textbooks were prepared, and the book publishing was established, etc. Under the leadership of V. Ilnytskyi, a number of other organizational measures were carried out at the gymnasium, including improving the financial situation of the institution and raising the level of staffing that generally contributed to the confirmation of its well-deserved authority in the national environment of Galicia. Vasyl Ilnytskyi also left an important mark in the history of the Ukrainian Pedagogical Society “Ridna Shkola”. On March 2, 1884, at the general meeting of the “Russian Pedagogical Society” at that time, he was elected as a chairman of the Main Department. Under his leadership, important measures were taken to raise the status of the Ukrainian language in educational institutions, improve womenʼs education, the social and legal status of public teachers, etc. Keywords: V. Ilnytskyi, Lviv Academic Gymnasium, “Russian Pedagogical Society”, “Prosvita” society, Ukrainian language, school textbooks, national education.