The study evaluated the empirical analysis of monetary policy and its effect on private sector growth in Nigeria; for the period 1990-2018. Secondary data were used and collected from the Central Bank of Nigeria Statistical Bulletin. The study used Private Sector Output is proxy for Private Sector growth and employed as the dependent variable; whereas, monetary policy rate, liquidity rate and Treasury Bills respectively were used as the explanatory variables to measure monetary policy. Hypotheses were formulated and tested using Ordinary Least Square (OLS) techniques. The study revealed a significant effect of Treasury Bills on private sector output in Nigeria. Liquidity ratio had a significant effect on private sector output in Nigeria. Monetary policy rate had a significant effect on6 private sector output in Nigeria. The coefficient of determination indicated that about 67% of the variations in private sector led- economy can be explained by changes in monetary policy variables. The study concluded that monetary policy had impacted significantly on private sector growth in Nigeria. The study recommended that strong macroeconomic policies should be employed to maintain and stabilize the economy. CBN should lay down strict prudential guidelines to stabilize and strengthen the private sector led-economy. Government and policy makers should formulate policies that will increase the flow of investable funds and improves the capacity of private economy.