This research is conducted to investigate determinants that affect delays in the signing of audit reports in Vietnam. The audit delay is measured as a function of the number of days that elapse from the accounting period until the date when the audit report is signed. This study employs a sample of 142 foreign direct investment (FDI) firms in Vietnam in 2019. We use Linear regression analysis, modelling audit delay as a function of the following explanatory variables: firm size, audit firm type, sign of income, audit opinion, and leverage. The findings indicate that the firms that report net income, that have standard audit opinion, and that have bigger size release their audited financial statements earlier. Variables such as auditor firm and leverage show no significant relationship with audit delay.