The research looked into how monetary policy affects economic activity and bank performance in different financial sector regimes. The data for this study were obtained from the Central Bank of Nigeria's (CBN) statistical bulletin. The study's goal was to look into the impact of monetary policy on bank performance, the relationship between monetary policy and bank reforms in Nigeria, and the relationship between bank policy changes and bank performance. The research was founded on theories of economic growth, monetary policy, and the financial sector. Return on Assets after Tax (ROA) is used as dependent variable in this study, while Monetary Policy Rate (MPR), Cash Reserve Ratio (CRR),Gross Domestic Product (GDP) and Interest Rate (INT) were used as dependant variables Monetary policy rates and cash reserve ratios have a negative impact on after-tax return on assets, whereas interest rates have a positive impact. The study recommended that, in the long run, relevant authorities in Nigeria's executive and legislative branches develop practical and feasible economic-friendly policies aimed at encouraging sustained and improved foreign investment inflows that can have a positive effect on the country's economy; the Central Bank's Monetary Policy Committee should also formulate and implement measures that would keep the interest rate and exchange rate at levels that would not have an adverse effect on the country's economy