Authenticity is being self-aware and living true to one’s self. Prior research has linked authenticity to important well-being outcomes, prompting a growing number of empirical studies on authenticity in workplace settings. Professional services firms provide a novel context to analyse the authenticity and well-being link, as these organisations are traditionally white, male-dominated environments and may promote an inauthentic climate for employees from marginalised groups. This study explores the associations between authenticity and well-being outcomes in a New Zealand (NZ) law firm and compares the authenticity of those from the dominant ethnic culture (NZ European) with those from other ethnicities. In addition, this research assesses whether gender and ethnicity intersect to create a double barrier for women from ethnic minorities, preventing them from being authentic at work. This study used an opportunistic mixed-methods approach and a cross-sectional research design to analyse secondary data collected in an online survey in March 2021 (N=181). Quantitative results revealed significant positive relationships between authenticity and both work engagement and job satisfaction. However, there was no support for the association between authenticity and mental health. Although ethnicity did not moderate the relationships between authenticity and well-being outcomes, NZ Europeans reported behaving more authentically at work than other ethnicities. There was no difference in authenticity by gender and no evidence of a double barrier preventing women employees from ethnic minorities to behave authentically at work. However, the supplementary qualitative analysis revealed potential challenges to authenticity among some women employees. Findings support the importance of enabling authenticity in the workplace for employee well-being. Theoretical and practical implications of these findings are discussed.