The Ukrainian Greek Catholic Church (UGCC) (Ukrainian: Українська Греко-Католицька Церква (УГКЦ), Ukrains'ka Hreko-Katolyts'ka Tserkva), is the largest Eastern Rite Catholic sui juris particular church in full communion with the Holy See, and is directly subject to the Pope. The Primate of the Church holds the office of Archbishop-Major of Kiev-Halych and All Rus, though the hierarchs of the church have acclaimed their primate "Patriarch" and have requested Papal recognition of, and elevation to, this title. The Church is one of the successor Churches to the acceptance of Christianity by Grand Prince Vladimir the Great of Kiev, in 988. The Church has followed the spread of the Ukrainian diaspora, and now has some 40 hierarchs in over a dozen countries on four continents, including three other metropolitans in Poland, the United States, and Canada. The head of the church is Major Archbishop Sviatoslav Shevchuk, since March 2011

Within Ukraine itself, the UGCC is a minority faith of the religious population, being a distant second to the majority Eastern Orthodox faith. The Ukrainian Greek Catholic Church is the second largest religious organization in Ukraine in terms of number of communities. In terms of number of faithful, the Ukrainian Greek Catholic Church ranks third in allegiance among the population of Ukraine, after the Ukrainian Orthodox Church (Moscow Patriarchate), and the Ukrainian Orthodox Church - Kyiv Patriarchate. Currently, the Ukrainian Greek Catholic Church predominates in three western oblasts of Ukraine, but constitutes a small minority elsewhere in the country.