People working in the music industry report significantly higher levels of anxiety and depression than the general population but to date, studies have not explored the differences between professional musicians and those who perform music primarily for recreation. In this study, 254 musicians from 13 countries completed measures of anxiety, depression, and wellbeing as well as answering questions about their professional status, level of success, and income. Across the whole sample, we found that over half had high levels of anxiety, and a third were experiencing depression. We showed that musicians who viewed music as their main career were more likely to have poor mental wellbeing and had significantly higher levels of clinical depression. Status as a solo or lead artist and perceived level of success also significantly predicted higher levels of anxiety and depression, and lower levels of positive wellbeing. We conclude that low mental wellbeing in musicians is the result of working as a professional musician, as opposed to being an inherent trait. Future work should explore underlying beliefs and perceptions of career musicians alongside other key factors, such as health behaviours and social support, with the aim of making specific recommendations to the music industries and educators.