The banking sector in Sri Lanka is one of the most dynamic and vibrant sectors of the economy. The banks are influenced by various types of risks and discrepancies which have a direct impact on the profitability of their short-term & long-term operations and sustainable capacity of earnings. The effective Assets Liability Management process will closely monitor and equalize both assets and liabilities and focus on the stability of adverse influences of both risks and discrepancies. The study aims to examine the significant impact of ALM on the financial performance of the licensed commercial banks in Sri Lanka from the financial year 2011 to 2020. Capital Adequacy Ratio (CAR), Non-Performing Loan Ratio (NPLR), Income Diversification Ratio (IDR), Liquidity Ratio (LR) and Operational Efficiency Ratio (OER) were used as asset liability indicators while Return on Assets (ROA) and Return on Equity (ROE) used as financial performance indicators. This study used secondary sources to collect data, such as published annual reports of licensed commercial banks and a central bank web site and selected all 24 licensed commercial banks in the population as the sample. The study used descriptive statistics, correlation analysis, and regression analysis to establish the relationship and effect of the ALM on the financial performance of the commercial banks in Sri Lanka. The findings indicate a significant negative relationship between NPLR and both ROE and ROA. The income diversification had a significant positive relationship with the ROA and also the ROE. Operational efficiency had a significant negative relationship with both ROE and ROA. The level of liquidity had a significant negative relationship with both ROA and ROE. The level of capital adequacy had a significant negative relationship with ROE. There is no significant relationship between CAR and the ROA. Based on the findings, which have the greatest implications for the policymakers who govern the financial performance of the banking sector, regulators who make regulatory requirements related to the banking sector, potential investors who invest in the banking sector and all other stakeholders & future researchers who are interested in the banking sector.