ObjectivesZZThe aim of this study was to develop the Korean version of the Warwick-Edinburgh Mental Well-being Scale (K-WEMWBS) and to examine its factorial structure, reliability, and convergent/discriminant validity. MethodsZZIn this study, the Warwick-Edinburgh Mental Well-being Scale (WEMWBS), a self-rating measure for assessment of mental well-being, was translated into Korean. It was completed by 222 respondents, including 117 healthy subjects and 105 psychiatric patients from both inpatient and outpatient clinics at Soonchunhyang University Hospitals in Bucheon, Cheonan, and Seoul. ResultsZZThe K-WEMWBS showed good content validity. Confirmatory factor analysis supported a single factor structure. The Cronbach’s alpha value for the K-WEMWBS was 0.944, which demonstrated good internal consistency. Test-retest reliability at 2–8 weeks was high (0.789). The K-WEMWBS showed high correlations with mental health, positive affect, and quality of life scales. Moderate negative correlation was observed between the K-WEMWBS and the negative affect scale. Discriminant validity was partially identified. Statistically significant differences in scores were observed between the psychiatric patient group and the control group. ConclusionZZThe results of this study indicate that the K-WEMWBS is a reliable and valid instrument for assessment of mental well-being, particularly the positive aspects of mental health.