This study examines empirically the structure and growth of federal government expenditure in Nigeria which has continued to increase since 1997. It has become a compelling debate about what is causing continued growth in government spending. Many factors have been identified as possible reasons for increased government spending, and investigations are needed to establish their impact on Nigeria. Time series data for the period of 1997 to 2018, were used in the study. The ordinary least squares (OLS) regression technique was employed as the main method of data estimation. The results obtained revealed that factors such as Fiscal Deficit, Real Gross Domestic product, Government Revenue and Debt Servicing are some of the factors causing growth in the government expenditure in Nigeria for the reference period. Therefore, governments are encouraged to maintain strong fiscal discipline, prevent double-digit inflation, and productively leverage revenue and productivity gains to curb growth in public spending 111 Nigeria.