This paper studies the relationship between Tunisian listed banks performance and two types of determinants; internal and external. The internal explanatory variables are: (1) the bank size, (2) privatization, (3) board size, (4) capital-to-assets ratio, and (5) cost of efficiency. The macro-economic (external) exogenous variables are: (1) gross domestic product growth rate and (2) inflation. Our panel-data analyses suggest a statistically significant and negative relationship between bank profitability (endogenous variable) and board size. However, the remaining variables were found to be statistically insignificant. This can be explained by two main sub-hypotheses: (a) state-owned banks included in the sample disturb the statistical significance of the results and (b) the year 2011 is a cut-off point that changed the Tunisian bank performance determinants.