Olagoke Odubunmi, in his article, The Role of Subsidiary Legislation in Tax Administration: A Review of the Judgment in FIRS V. Checkpoint Software Technologies B.V. Nig. Ltd., examines the role of subsidiary legislation in the Nigerian tax administration. Odubunmi provides detailed rules, regulations, and guidelines that operationalize the broad provisions of principal tax statutes, thereby ensuring effective tax administration, compliance, and enforcement. While Subsidiary Legislation, as defined within the context of Section 37 of the Interpretation Act, refers to “any order, rules, regulations, bylaws, rules of court etc., made by executive and administrative agencies of government in exercise of powers conferred by an Act of the National Assembly, they however remain subject to the authority of the National Assembly and the supervision of the courts through judicial review. Within this context, the author reviews the case of (FIRS v Checkpoint Software Technologies B.V Nig. Ltd), as it highlights the place, role, extent, and limitations of subsidiary legislation in Nigerian taxation. Findings from the case review reveal that: Where the terms and conditions for making regulations by tax authorities as donated by the legislature are breached, any instrument produced through the defective process will be declared null and void by the court. Also, where Tax and revenue agencies make subsidiary legislation to give effect to the provisions of relevant tax laws (e.g., on the imposition of penalties), the revenue agency lacks the power, through regulation, to impose higher penalties beyond what is stipulated in the principal legislation. Similarly, the regulations made by Tax Authorities to give effect to international treaties or agreements are void and unenforceable in Nigeria until domesticated by the National Assembly as compulsorily required by Section 12 of the 1999 Constitution.