The problem addressed in this paper is the persistent tension between the legislature and the executive in Nigeria, which often undermines effective policy formulation and implementation, particularly in sensitive reforms such as taxation. Nigeria’s 2025 Tax Reform Initiatives have generated intense legislative–executive interactions that raise concerns about coordination, accountability, and policy coherence. The objective of this paper is to examine the nature of legislative–executive relations in the context of the 2025 Tax Reforms, identify ideal practices, and assess their implications for nation-building. The paper adopts a qualitative research design, relying on secondary sources including scholarly literature, government policy documents, legislative debates, budget statements, and reports from relevant institutions. Data are analyzed using content analysis to identify recurring themes, institutional patterns, and governance gaps in the reform process. The findings reveal that cooperative legislative–executive relations enhance policy legitimacy, fiscal transparency, and reform sustainability, while adversarial relations delay reforms, politicize taxation, and weaken public trust. The paper further finds that inadequate consultation, weak institutional autonomy, and partisan interests limit the effectiveness of tax reforms and their nation-building outcomes. The paper concludes that constructive legislative–executive collaboration is critical for successful tax reform, nation-building and sustainable national development in Nigeria. It recommends strengthened inter-branch dialogue, respect for constitutional roles, evidence-based lawmaking, and inclusive stakeholder engagement in tax policy processes. The contribution to knowledge lies in situating Nigeria’s 2025 tax reforms within the broader framework of legislative–executive relations, providing an analytical lens for understanding how governance dynamics shape fiscal reform outcomes in developing democracies.

Keywords: Legislative–executive relations, Tax reform, Fiscal policy, Nation-Building, Governance, Nigeria.