The financial crisis had significant implications for the fiscal positions of nations. As nations seek to cope with the economic contraction, budget deficits and debt have risen to near record postwar levels. Fiscal responsibility and Fiscal Responsibility Laws (FRLs) are invoked in the process of managing public finances and related institutional mechanisms, with the aim of increasing the transparency in the management of financial resources and assuring the correction of the public deficit and debt. The study aims to assess the instrumentality of the Fiscal Responsibility Act (FRA), 2007 on public expenditure in Nigeria. The public choice theory of fiscal responsibility was used as a theoretical basis for the study. The study adopted a mixed methodology comprising of both quantitative and qualitative approaches to carry out investigation. Documentary sources were used for data collection, while descriptive statistics and content analysis were used for the data analysis. Findings of the study showed that the FRA has not served as a potent control mechanism of public expenditure in Nigeria. The study also revealed that shortfalls of the FRA in Nigeria are evidenced by poor fiscal outcomes such as revenue shortages, bloated expenditures, fiscal deficits and public debt accumulation. The study recommends that review of the FRA and strict application of economic principles in financial management are critical measures that should be adopted to improve fiscal responsibility in Nigeria’s public expenditure.