The Patriarch of Moscow, Kirill I, is a divisive figure in Orthodox Christianity. His loyalty to Vladimir Putin, particularly concerning the war in Ukraine, has created tensions between the Russian Orthodox Church and much of the rest of the Orthodox world. After war began in Ukraine in 2022, Kirill said that Russian soldiers should know that “sacrifice washes away all the sins that a person has committed.” He has also been keen to congratulate nondemocratic leaders in countries allied with Russia, such as Alexander Lukashenko of Belarus. To what extent do Orthodox Christians in Belarus and Ukraine reflect their countries’ widely divergent relationships with Russia through allegiance (or lack thereof) to the Patriarch of Moscow? We ask whether the extent and structure of support for the Patriarch of Moscow looks differently when comparing respondents in Belarus and Ukraine. We base our analysis on the Pew Research Center’s Religion and Social Life in Central and Eastern Europe Survey, which was conducted in 2015. We model two dependent variables, both of which measure allegiance to the Patriarch of Moscow. The first is a question asking respondents whether they consider a variety of Eastern Orthodox leaders “a source of moral authority in [their] life.” Respondents could identify more than one leader in answering this question. The second is the question “Who do you recognize as the highest authority of the Orthodox Church?” How do political and religious factors affect responses to these questions, and to what extent do the predictors of allegiance to Kirill vary in two countries that have such different relationships with Moscow?