The purpose of this study is to determine the effect of chief executive officer duality on the profitability of money deposit banks. The research design adopted by this study is the quantitative approach. The population of interest for this study comprised the twenty-two deposit money banks listed on the Nigerian Stock Exchange (NSE) as at March (2016) for the period of sixteen years from 2000 to 2016. The study utilized only the secondary source of data. There exists a negative relationship between CEO duality and profitability. This further entails that for the sampled banks, CEO duality contributes negatively to the profitability of the selected money deposit banks in Nigeria. The coefficient of determination which measures the control power of the independent variable over the dependent variable was calculated with the instrument of adjusted R-Squared and it yielded 0.296170. This entails that the variations in profitability of the selected deposit money banks is not significantly influenced by CEO duality. Based on the findings, the study concludes that on the average, effect of chief executive officer duality has no significant effect on the profitability of money deposit banks. This finding reveals that dual role has no positive and significant influence and contribution towards profitability in money deposit banks. This should be thoroughly ascertained for it to be either suspended or significantly minimized.