Abstract
This study investigated the effect of board heterogeneity on the financial performance of listed deposit money banks in the ECOWAS sub-region, specifically analysing how skill and professional background diversity and ethnic and cultural diversity, influence financial performance metrics Return on assets (ROA)and Tobin's Q. An ex post facto research design was employed, utilizing audited annual reports from Zenith Bank and United Bank for Africa (UBA) for the period 2008 to 2023. The data were analysed using regression models to identify significant effect between board diversity and financial performance. The findings indicate that neither skill and professional background diversity nor ethnic and cultural diversity have a statistically significant effect on financial performance of the listed deposit money banks of the ECOWAS sub-region. These results suggest that other governance variables, institutional factors, or economic conditions may be more influential on bank performance. The study recommends exploring additional variables and emphasizes the importance of effective governance practices alongside diversity initiatives to enhance bank financial performance in the ECOWAS banking context.