This article evaluates the factors affecting the use of management accounting in small and medium enterprises (SMEs) in Hanoi, Vietnam. The factors include: Production and business characteris-tics; Competitiveness; Business strategy; CEO of awareness management; Human resource quality. The study is conducted on 238 SMEs in Hanoi and the results show that CEO’s awareness of management accounting had the strongest impact on the ability to apply management accounting of enterprises while competition level factor had the weakest effect. At the same time, the study also examines the significant role of mediating factor of firm size on the relationship between the charac-teristics of the production and business process and the application of management accounting, age and professional qualifications. The results indicate that enterprise size plays a significant role on regulating the impact of business characteristics of enterprises on management accounting applica-tion. For smaller enterprises, management accounting is less used and vice versa. Next, the younger the managers are, the higher the impact of their awareness on management accounting application, which means management accounting will be used more if managers are younger.