Financial statements of Vietnamese commercial banks must be audited annually by an auditing firm according to the Government’s regulations. This study identifies factors associated with firm performance and external audit selection. The decision to choose an auditing firm is considered an intermediate variable to determine the degree of impact of some factors on the performance of commercial banks. This study was conducted by interviewing 265 managers holding high positions as CEOs and CFOs at 30 commercial banks in Vietnam. The non-probability sampling method was applied. The survey was produced using Google Forms and sent directly to participants. Structural Equation Modeling (SEM) is applied to test hypotheses. The results show that except for the complexity of a firm, the factors such as legal environment, audit fees, audit firm size and reputation, bank governance, audit experience, and relationship positively impact external auditor selection. Besides, external auditor selection significantly affects firm performance. This study’s conclusions from the viewpoints of bank managers open the door to promising and timely future research. It is necessary to deepen and broaden academic understanding of the ideas and determining elements influencing external auditor selection and firm performance. More research is needed to fully comprehend this problem and move towards a policy solution.