The aim of this study was to assess the validity of the Warwick-Edinburgh Mental Well-being Scale used for measuring mental well-being. Nursing students' mental well-being is often poor due to various academic and personal stressors. Nursing students are involved in clinical practice and are facing birth, death, health, diseases and other stressful situations. They may be exposed to higher levels of stress than students from other study programmes. A cross-sectional study was conducted among nursing students in Slovenia. We performed a 6-step analysis of the psychometric properties of the Warwick-Edinburgh Mental Well-being Scale. Moreover, content validity of the scale was assessed. The scale formed a unidimensional scale with good homogeneity (H<0.40) and reliability (α=0.91; β=0.87; λ=0.92; ω=0.91). The confirmatory factor analysis suggested that the WEMWBS was suitable for use as a single scale (RMSEA=0.085, CFI=0.907; TLI=0.891) and measures one construct, mental well-being. I-CVI is acceptable for all 14 items, kappa coefficient was excellent, and S-CVI was assessed as acceptable. The Slovenian version of the scale achieved good validity and reliability in a sample of nursing students and is recommended for future usage. The validated questionnaire can be used by nurse managers to assess nursing students' mental well-being during their clinical placement.