Previous research has established a robust relationship between symptoms of social anxiety and disordered eating. However, the mechanisms that may underpin this relationship are unclear. Appearance-based rejection sensitivity (ABRS)—the tendency to anxiously expect and overreact to signs of appearance-based rejection—may be a crucial explanatory mechanism, as ABRS has been shown to maintain social anxiety symptoms and predict disordered eating. We therefore tested whether ABRS mediated the relationship between social anxiety symptoms and various indices of disordered eating (over-evaluation of weight/shape, restraint, binge eating, compulsive exercise, and vomiting). Data from community-based females (n = 299) and males (n = 87) were analyzed. ABRS was shown to mediate the relationship between social anxiety and the over-evaluation, restraint, binge eating, and compulsive exercise frequency, but not vomiting. These effects also occurred for both females and males separately. Findings demonstrated that ABRS may be an important mechanism explaining why socially anxious individuals report elevated symptoms of disordered eating. Future research testing all proposed mediating variables of the social anxiety-disordered eating link in a single, integrative model is required to identify the most influential mechanisms driving this relationship.