Purpose of the study: The purpose of the study was to critically analyze the effectiveness of banks’ performances and to examine the associations amongst the asset management, banks’ size, operational efficiency, and their impact on the bank’s performance. Design/Methodology/Approach: The secondary data was obtained from the annual reports of five selected commercial banks of Oman listed in the Muscat Securities Market (MSM) for the period 2013 to 2019. The collected data was analyzed through financial ratios using excel and SPSS and was used to evaluate the banks’ performance. Findings: The study revealed that the Operational Efficiency (OE) of the selected commercial banks had an impact on the Return on Assets (ROA); advances of the selected commercial banks had an impact on the interest income whereas operational efficiency of the selected commercial banks had NO impact on the Interest Income. The study further confirmed that Bank Muscat proved to be the bank that performed well over the years 2013 to 2019. Research Implications: The study proved that the banks’ financial performances can be measured through the assets size, asset management, and equity management using ratio analysis which can be a good measure to adjudge the financial performances of the banks. Social Implications: The study helps the stakeholders of the banks to understand the factors and the banking activities that might help to enhance the financial performances of the banks and to take necessary action and suitable decisions accordingly. Originality/value: The study was restricted to five selected commercial banks of Oman and the study had relied mostly on quantitative techniques involving ratio analyses. The study can be extended to all the commercial banks in Oman including the most determining factor viz. customer satisfaction. Keywords: Financial Performance of Banks, Operational Efficiency, Return on Assets, Return on Equity, Interest Income, Ratio Analyses