Evidence of the high prevalence of physical and psychological problems among professional and student classical musicians has led to investigations of music students’ health-promoting behaviours. These have indicated lower levels of engagement in health-promoting behaviours among music students compared to non-music students and resulted in the recent introduction of health education courses in a number of tertiary music education institutions. Investigations of health-promoting behaviours in a wide range of contexts have shown that personality and general self-efficacy are significantly associated with health-promoting behaviours. Although previous studies of music students’ health-promoting behaviours provide evidence of positive associations between general self-efficacy and health-promoting behaviours, the contribution of personality to health-promoting behaviours and the influence of general self-efficacy on the associations between personality and music students’ health-promoting behaviours have not yet been investigated. The current study examined associations between the personality, general self-efficacy, and health-promoting behaviours of 154 undergraduate music students. Hierarchical regression analyses showed that Conscientiousness was the most consistent significant predictor of health-promoting behaviours. Conscientiousness, Extraversion, and Neuroticism were found to predict general self-efficacy. Mediation analyses were carried out and showed that general self-efficacy mediated the associations between both Conscientiousness and Neuroticism, and health-promoting behaviours. The implications of the findings for future health education courses are discussed.