Abstract Background We aimed to validate the Warwick-Edinburgh Mental Well-being Scale (WEMWBS) among English speaking adults representing two of the minority ethnic groups living in the UK, self-identified as Chinese or Pakistani by background, in a mixed methods study. Methods Quantitative data were collected in two cities in the West Midlands, UK. Item response, dimensionality, internal consistency, and construct validity of the WEMWBS were assessed in Chinese and Pakistani groups separately, using data from both cities combined. Qualitative data were collected in the first city in eight focus groups of different ages recruited by the community workers. Three mixed sex Chinese and five single sex Pakistani groups discussed ease of completion and comprehension of items, together with overall reactions to the scale and underlying concept. Results of quantitative and qualitative analysis were examined for commonalities and differences. Results Item completion and item total correlations were satisfactory in both groups. In the Chinese data, Exploratory Factor Analysis showed a single factor with loadings ranging from 0.60 to 0.82 for all 14 items. In the Pakistani data, three factors reached statistical significance; however, a substantial drop in eigenvalues between the first and second factors and the limited variance explained by the second and third factors supported a one-factor model. All items loaded on this factor from 0.51 to 0.83. In the Chinese and Pakistani data respectively, Cronbach’s alpha was 0.92 (0.89 – 0.94) and 0.91 (0.88 – 0.94); Spearman’s correlation with GHQ-12 was - 0.63 (−0.73 to −0.49) and −0.55 (−0.70 to −0.36), and with the WHO-5 0.62 (0.46-0.75) and 0.64 (0.50 to 0.76). Qualitative analysis revealed good comprehension and ease of completion of almost all items. Some culturally determined differences in understanding of mental well-being, which varied both between and within communities, emerged. Conclusions The WEMWBS was well received by members of both Pakistani and Chinese communities. It showed high levels of consistency and reliability compared with accepted criteria. Data were sufficiently strong to recommend the WEMWBS for use in general population surveys.