The main objective of this study was to determine the effects of Corporate Governance on the financial performance of listed companies in Rwanda Stock Exchange (RSE). Particularly, the present study examined the effects of board size, board composition (gender: male or female and directorship: executive or non-executive), CEO duality and financial leverage on the financial performance of listed companies in RSE. Firm performance was measured using Return on Assets (ROA), Return on Equity (ROE) and Tobin’s Q. The study population included all the companies listed in RSE for the years 2010 to 2015 hence census sampling approach. The secondary data were collected from audited and published financial statements, RSE handbooks and Capital Markets Authority (CMA) online libraries. Both descriptive and inferential statistics were used. Pearson’s bi-variate correlation was used to establish the direction, strength and significance of relationships between corporate governance and firm performance while ordinary Least Squares regression model was used to explain variation in the dependent variables; ROE, ROA and Tobin’s Q upon the confirmation of fixed and random effects methods using Hausman tests. The results indicated a significant positive correlation between profitability and firm age on firm performance. However, board composition (directorship and gender) and financial leverage were negatively correlated with the financial performance of firms in RSE. Econometric estimates indicated that corporate governance contributed to 60.1%, 93.1% and 91.1% variations in ROE, ROA and Tobin’s Q respectively. Consequently, 1% increase in profitability decreases ROE by 5%. On the other hand, 1% decrease in financial leverage increases ROE by 4%. It was also established that 0.01 increase in profitability increases return on assets by 102%. The management should therefore invest more on profitability of the firms listed at RSE in order to improve firm performance. More consideration should be given to board size, board composition and financial leverage in order to maximize shareholder’s equity. The study concludes that there is a strong positive relationship between corporate governance practices and the overall performance of firms listed at RSE. However, smaller board sizes, greater financial leverage and dominance of the board by either gender negatively affects the financial performance of firms listed at RSE.