This dissertation examines the jurisprudence of the Constitutional Court of the Russian Federation on religious freedom, focusing on the role of the Russian Orthodox Church (ROC) in shaping constitutional interpretation and practice. It analyzes the ROC not merely as an object of regulation but as an active institutional and political actor in state-religion relations. The central research question concerns the extent to which the ROC influences constitutional trends through the Court's decisions. The study combines legal analysis and case studies of key rulings, alongside an examination of state-church interactions. Part I outlines the legal framework governing religious organizations, highlighting unequal treatment of traditional and non-traditional groups. Part II explores the ROC's influence on legislation, judicial interpretation, property rights, and responses to major socio-political events, including the war in Ukraine. The analysis shows that, despite constitutional guarantees of religious equality, the Court's jurisprudence consistently favors the ROC and other "traditional" religions. Minority and non-traditional groups face restrictive registration, limits on missionary activity, and selective use of anti-extremism laws. These inequalities are reframed as constitutional pluralism, producing a hierarchical system in which formal equality conceals substantive disparities. The dissertation's originality lies in its systematic analysis of the Constitutional Court's jurisprudence, a field rarely addressed in Western scholarship. It identifies the legal mechanisms through which constitutional principles are adapted under ROC influence and offers a framework for comparative analysis. The study concludes that the ROC functions as a strategic actor embedded in the legal system, reinforcing a model in which formal secularism coexists with the privileging of a dominant religion, with significant consequences for religious pluralism and minority rights.