This study aimed to investigate the relationship between corporate governance and financial ratio with the performance of companies listed on the stock exchange of Thailand with an excellent score. The data were collected from annual registration statement (Form 56-1) of 191 companies from 2016 to 2020. Descriptive statistics such as mean percentage standard deviation and Inferential statistics such as Pearson’s Correlation Coefficient and Multiple Regression Analysis were used to examine the relationship. The results showed that 1) Corporate Governance namely Board size the ratio of independent director and Managerial Ownership positively corelated with firm performance. 2) Leverage Ratios (Financial Ratio) namely Debt to asset ratio and Debt to equity ratio negatively corelated with firm performance but Interest coverage ratio positively corelated with performance