This systematic review examined trends in the prevalence of type 2 diabetes mellitus (T2DM) and identified its risk factors among adults in Vietnam. PubMed, Web of Science, Wiley Online Library, and Scopus databases were searched to identify relevant literature. The search yielded 10 studies, including 2 national surveys and 8 regional investigations. National prevalence estimates of T2DM were 2.7% in 2002 and 5.4% in 2012. The estimates for the northern region were 1.4% in 1994 and 3.7% in 2012 and those for the southern region were 3.8% in 2004, 7.0% in 2008, and 12.4% in 2010. The major determinants of T2DM included older age, urban residence, high levels of body and abdominal fat, physical inactivity, sedentary lifestyle, genetic factors, and hypertension. The prevalence rate by gender was variable in both national and regional studies. There was insufficient information available on some potentially important risk factors such as smoking, dietary intake, income, and educational level. Our review signifies a rapidly growing prevalence of T2DM in Vietnam and suggests that extra effort is required to prevent and control this disease