This study has primary two aims. The first is to determine the characteristics of boards of directors in the Turkish banking industry and the second is to investigate the effect of board diversity on performance of the banks. The analyses in this study are built on the banking industry of Turkey in the period from 2008 to 2012. The impact of the board diversity, as measured by the percentage of women and foreign directors on the board and the Blau index, on financial performance is investigated by conducting panel data analysis. The findings of the study provide evidence of a negative relationship between board diversity and financial performance. Hence, the findings do not support the economic case for board diversity, which implies that diverse directors will increase the financial performance of the banks. This study provides additional evidence to the sparse literature regarding the association between board diversity and financial performance in an emerging market context. Furthermore, most prior studies regarding the relationship between gender diversity and performance have excluded financial firms from their samples. In addition, there are few studies that examine the impact of foreign directors on the performance of banks.