Background Chronic noncommunicable diseases (NCDs) associated with excess weight as a significant risk factor, but few studies have been sufficient enough to examine the magnitude of excess weight of Vietnamese adults. This review aimed to provide a generalized estimate of the prevalence of excess weight among Vietnamese adults. Methods PubMed, Scopus and national database were used to identify articles published up to May 2022. The Newcastle-Ottawa Quality Assessment Scale was used to rate the study quality. The data was analyzed using RStudio software, and the combined effects were estimated using random-effects meta-analysis. The Cochran's Q-test and the I2 test were employed to examine heterogeneity, and subgroups were conducted. Egger's test and visual inspection of the symmetry in funnel plots were used to determine publication bias. Results 58 studies with 432,585 participants from 1998 to 2020 were suitable for inclusion in the final model after meeting the prerequisites. Over the last three decades, the combined pooled prevalence of excess weight among adults in Vietnam was 20.3% (95% CI: 15.2–26.6). Notably, this proportion has a tendency to go up between 1998 and 2020. Moreover, rates of excess weight were found to be substantially higher in non-national studies (23.1%, 17.3–30.1) compared to national studies (8.4%, 3.6–18.3) and significantly higher when Asian and Pacific cut-offs (27.6%, 20.0–36.7) were used rather than WHO classification (11.2%, 6.7–18.0). Conclusion The findings suggest healthcare professionals and policymakers should focus more on designing and implementing preventive initiatives to lower the rising prevalence of excess weight adults in Vietnam.