The study sought to evaluate the causal link between audit fees paid by Deposit Money Banks in Nigeria and their financial performance. Ex-post facto research design was adopted for the study where panel data extracted from the financial reports of ten (10) banks in Nigeria for the periods 2014 to 2020 were used. The dependent variable was financial performance measured with return on asset while the independent variable was audit fee. The variables were moderated with firm size and leverage. Generalized Method of Moments (GMM) Model was used to analyze the data under E-views version 10. The result revealed that audit fee has a positive and significant influence on financial performance of banks while firm size and leverage show negative but significant relationship with financial performance. The study therefore concludes that audit fee positively influences the financial performance of banks in Nigeria. The study recommends among others that bank management should ensure that audit fees charged by the auditors translate to better audit quality which is the reliance of financial users.