Objective This study examined the factor structure and measurement invariance of the Mental Health Continuum‐Short Form (MHC‐SF) in young adults from Iran and the USA and across gender. Method The sample consisted of 387 Iranian and 395 American university students. Confirmatory factor analysis (CFA) and the new method of exploratory structural equation modeling (ESEM) were used to analyze the data. Results The three‐dimensional model of well‐being as measured by the MHC‐SF was consistent with the data. ESEM resulted in better fit indices as well as considerably lower factor correlations than did CFA. Partial measurement invariance across nations and full measurement invariance across gender were established. Conclusion The results confirm the three‐dimensional structure of mental well‐being, and indicate that the items of the MHC‐SF function largely similarly across the two nations. These results also showcase the unique value of ESEM in understanding the factor structure of mental well‐being.