While boards are the main tool of internal governance mechanism, their efficacy may vary depending on their diversities. This study examined the impact of Board of Directors‟ heterogeneity on the financial performance of listed deposit money banks in Nigeria. This area of board diversity especially the ethnic diversity is still a novel area of research in Nigeria. The financial performance in this study was the dependent variable while nationality, gender and ethnic composition of Board of Directors were the independent variables. 

The population of the study consists of fifteen (15) listed deposit money banks in Nigeria as at 31st December 2012. Eleven of these banks constituted the sample size for the period of eight years (2005-2012). The study employed multiple regressions as a tool for analysis. Secondary data obtained from the financial statements of the companies were analyzed. The result showed that gender and ethnicity of board directors had positive and significant impact on banks financial performance while, nationality of the board of directors showed a negative but significant relation to banks financial performance. 

For banks to achieve greater returns in the market, it is recommended that ethnic composition of Board of Directors of listed deposit money banks in Nigeria should be integrated into the corporate governance practices as allowing for a more ethnic balance translates into better financial performance.