Modern society faces an increasing threat from religious and religious-political extremism, which manifests through the radicalization of consciousness, violence, the undermining of secular foundations of the state, and the rise of interfaith tensions. Despite the existence of legal and institutional mechanisms to counter this phenomenon, it remains pressing due to its transnational nature, the ideological adaptability of extremists, and their ability to disguise their actions as religious activity. A particularly critical issue is the clear distinction between religious and religious-political extremism to enable effective prevention and response. To reveal the essence and specifics of religious and religious-political extremism, define their key features, causes, and forms of manifestation, and propose comprehensive approaches to countering this phenomenon by the state, society, and religious organizations. The study employs a systemic, comparative-legal, sociological, and political science approach. It includes the analysis of legal acts, international agreements, expert opinions, and empirical material, including case studies of extremism and countermeasures from various countries. The study establishes that religious-political extremism represents a distinct form of illegitimate political struggle, disguised in religious rhetoric and aimed at dismantling the constitutional order and territorial integrity of the state. It identifies key distinctions between religious and religious-political extremism and highlights the risks of conflating the two in legal practice and public discourse. The paper proposes improvements to legislation, enhanced preventive and educational work, and a stronger role for religious leaders and civil society institutions in combating radicalism