This study aimed to verify the validity of a measurement tool for Vietnamese high school students’ systemsthinking abilities. Two quantitative assessment tools, the Systems Thinking Measuring Instrument (Lee et al., 2013) andthe Systems Thinking Scale (Dolansky et al., 2020), were used to measure students’ systems thinking after translation intoVietnamese. As a result, it was revealed that Cronbach-α for each tool (i.e., STMI and STS) was .917 and .950,respectively, indicating high reliability for both. To validate the construct validity of the translated questionnaire,exploratory factor analysis was performed using SPSS 26.0, and confirmatory factor analysis was performed using AMOS21.0. For concurrent validity, correlation analysis using structural equation modeling was performed to validate thetranslated questionnaire. Exploratory factor analysis revealed that 10 items from the STMI and 12 items from the STSloaded on the intended factors and appropriate factor loading values were obtained. For confirmatory factor analysis, astructural equation model organized with 10 items from the STMI and 12 items from the STS was used. The result ofthis showed that the convergent validity values of the model were all appropriate, and the model fit indices were analyzedto be χ2/df of 1.892, CFI of .928, TLI of .919, SRMR of .047, and RMSEA of .063, indicating that the model consistingof the 22 items of the two questionnaires was appropriate. Analysis of the concurrent validity of the two tools indicated ahigh correlation coefficient (.903) and high correlation (.571-.846) among the subfactors. In conclusion, both the STMIand STS are valid quantitative measures of systems thinking, and it can be inferred that the systems thinking ofVietnamese high-school students can be quantitatively measured using the 22 items identified in our analysis. Using thetool validated in this study with other tools (e.g., qualitative assessment) can help accurately measure Vietnamese highschool students’ systems thinking abilities. Furthermore, these tools can be used to collect evidence and support effectiveeducation in ODA projects and volunteer programs.