This study investigates the impact of corporate governance on firm performance in Nigerian economy. Corporate governance has been the focal point of developing economies because it helps promote accountability, transparency and effectiveness of organizations. The study investigates listed firms on the Nigerian Exchange Group (NGX) by employing the quantitative research design. Data were collected from annual reports and audited financial statements of some selected companies and then treated as secondary data. The corporate governance is proxies by the size of the board, independence of the board, and ownership structure while the firm performance is measured by ROA and ROE. Descriptive statistics and regression analysis were conducted with the use of SPSS for the analysis of the data. From the descriptive statistics it is observed that the selected listed firms on NGX operate with a moderate board size with variable board independence and ownership concentration. The analysis of the data reveals that there is a positive and significant impact of all corporate governance factors on firm performance, and out of these the board independence has a very high positive and significant impact on ROA than any other factors and then the ownership structure and board size respectively. Also, the firms with high governance have high financial performance. Finally, it is found that the firm performance in Nigerian listed firms depends on corporate governance mechanisms which help to eliminate agency problem and increases the manager’s accountability. So it is concluded that it should maintain moderate board size and high board independence, increase ownership transparency so as to increase firm performance and investor’s confidence and all regulatory authorities should try to maintain all corporate governance codes to ensure a sustainable growth in corporate in Nigerian context.

Keywords: Board independence, board size, ownership structure, agency theory, listed firms.