Narcissism, which features the chronic disposition to seek the opportunity to construct and maintain an inflated self, is a known risk for antisocial behaviour. However, knowledge of factors that mitigate the effects of narcissism on antisocial behaviour is lacking. In two studies we explored the hypothesis that self-compassion would protect against the link between narcissism and antisocial behaviour, such that narcissism would be less related to antisocial behaviour when self-compassion was high. Study 1 was a cross-sectional study with a sample of professional footballers (N = 208). Study 2 utilised a sample of competitive athletes from a variety of sports (N = 324) over an eight-month period. The data from both studies supported the hypothesis: Greater self-compassion was associated with a null (Study 1) or significantly attenuated (Study 2) relationship between narcissism and antisocial behaviour. We discuss the implications of the findings, including the benefits of incorporating self-compassion in sport settings.