The role of the audit committee in maintaining banking stability is becoming increasingly important. However, there are not many studies have examined the relationship between the audit committee structure and bank stability in developing countries. This paper examines the relation of the audit committee structure and the bank stability in the difference level of bank stability and the role of external audit quality in this relation by employing empirical techniques like 2SLS, S-GMM or quantile regression analysis with panel data, and using a sample of 37 commercial banks in Vietnam from 2002 to 2018. Our empirical results show that bank stability varies negatively with audit committee size, but this relationship is mitigated in banks that use good external audit services. Moreover, we also find that the relation of the audit committee structure and bank stability is heterogeneous, and that it is stronger in banks with higher stability levels. Based on these results, banks that have a large audit committee should consider a high quality external audit service and should increase the proportion of financial and accounting expertise in the audit committee in order to ensure bank stability.