This paper increases the understanding of the quality of accounting information systems in emerging economies, using data from Vietnam as an example. The quality of accounting information systems is a measure combining system quality and information quality. It is important to figure out what aspects of this measure are critical for business to enhance firm performance. This research investigates the level of accounting information system quality and examines the relationships between system quality and firm size, information quality and firm size, system quality and business sector as well as information quality and business sector, respectively. We employed descriptive statistics to illustrate the quality of accounting information systems and One-Way ANOVA to test four hypotheses. The descriptive statistics results demonstrate the level of system quality and information quality, in general, is not excellent. And there are differences in system quality and information quality in each business sector groups and firm size groups. The test result highlights a relationship between system quality and firm size but there are no links between information quality and firm size, system quality and business sector, and information quality and business sector. In conclusion, the paper extends the literature of the quality of accounting information systems and assists state agencies and executives to have a framework to improve the business performance as well.