Religion has remained a significant factor in Nigeria's political landscape, influencing electoral processes, governance, and intergroup relations. While religious diversity has the potential to foster tolerance and national cohesion, its politicization has increasingly generated political polarization, weakened democratic governance, and threatened national unity. The use of religious sentiments by political actors for electoral advantage has contributed to social divisions, distrust among religious groups, electoral violence, and challenges to equitable governance. This study examined the effect of religious politicization on federal governance and national unity in Nigeria. Specifically, the study investigated the extent to which religious politicization influences governance, assessed its impact on national unity, identified the factors promoting religious politicization in Nigerian politics, and examined possible strategies for promoting religious tolerance and inclusive governance. The study adopted a case study research design. The findings revealed that religious politicization has a significant effect on federal governance in Nigeria. The analysis further reveals that religious politicization has adversely influenced national unity in Nigeria. Based on these findings; the study recommended that the Federal Government should ensure that appointments into public offices are based on competence, merit, and constitutional principles rather than religious affiliation. Government should strictly uphold the constitutional principle of religious neutrality by ensuring equal treatment of all religious groups in policy implementation, resource allocation, and political representation. Government, religious leaders, and civil society organizations should intensify interfaith dialogue, peacebuilding initiatives, and public enlightenment campaigns aimed at promoting religious tolerance, mutual respect, and peaceful coexistence among Nigeria's diverse religious communities. And educational institutions, the National Orientation Agency, and other relevant stakeholders should promote civic education that emphasizes national identity, constitutional values, democratic principles, and responsible political participation.