ABSTRACTThe DASS‐21 has been widely used in university student mental health research. However, studies on its cross‐cultural reliability and validity, particularly among Eastern student populations, remain limited. This study examined the DASS‐21's psychometric properties and measurement invariance across Australian, Chinese and Vietnamese students. Data were drawn from multiple surveys conducted between 2017 and 2021, comprising 2420 university students from Australia (n = 1093), China (n = 626) and Vietnam (n = 701). Single‐group confirmatory factor analyses (CFAs) supported the three‐factor model of the DASS‐21 with acceptable fit for each cultural group, requiring minor modifications for Chinese and Vietnamese data. Multiple‐group CFAs resulted in an 18‐item version (DASS‐18) that achieved cross‐group measurement invariance and acceptable internal consistency. Non‐parametric tests revealed the lowest scores for all the DASS‐18 results among Australian students, while Chinese students reported the highest level of anxiety and Vietnamese students reported the highest level of depression. The two Asian samples exhibited similar levels of stress and overall distress. In general, this study supports the measurement invariance of the DASS, with caution regarding culturally sensitive items. Implications for the DASS‐21's universality and recommendations for future research and multicultural psychological assessment are discussed.