Government has the responsibility to ensure the betterment of the life of her citizens through policies made for effective and efficient delivery of services. This paper examines the policy of Treasury Single Account (TSA) adopted by the Federal government in 2015 and how it has been ensuring accountability and transparency in the public sector. It made use of qualitative approach with an expo-facto design and secondary sources of data collection. Over the years, Nigeria has been bedeviled with massive looting, embezzlement and misappropriation of the public funds which has culminated in economic recession and fiscal imbalance in recent times. TSA therefore was primarily adopted to ensure accountability of government revenue, enhance transparency and avoid misappropriation of public funds. The paper observes that with the TSA, government have been blocking loopholes and leakages of financial resources and also ensure a robust financial management system. It observes further that TSA has helped to ensure proper cash management by eliminating idle funds usually left with different deposit money banks and enhance reconciliation of revenue collection and payment. As robust and encouraging the TSA policy can be, the paper discovered that lack of legally recognized regulatory agency, non-adoption of e-governance initiative and erratic supply of electricity are some of the challenges capable of truncating the future operational relevance of TSA. Thus, the paper recommended among others, the need for a cooperative collaboration between the executive and legislative arms in establishing an institutionalized agency TSA operations domicile in the Federal Ministry of Finance but report directly to the Presidency for accountability and transparency. Keywords: Accountability, Good governance, Governance, Transparency and TSA.