Eating disorders and social anxiety are highly comorbid. Understanding this comorbidity may improve treatment outcomes, as social anxiety can impair the ability to benefit from eating disorder treatment. The primary model of social anxiety and eating disorder comorbidity includes social appearance anxiety, high standards, and maladaptive perfectionism. In the current study, we tested for ethnic invariance between Asians (n = 82) and European Americans (n = 182) in a cross-sectional and prospective comorbidity model of social anxiety and eating disorder symptoms. Differences were found across ethnicity in eating disorder and social anxiety symptom comorbidity. Maladaptive perfectionism predicted social anxiety and eating disorder symptoms in European Americans, whereas social appearance anxiety predicted social anxiety and eating disorder symptoms in Asians. Our findings suggest that interventions for social anxiety and eating disorders in Asian populations may be improved by assessing and targeting social appearance anxiety, while maladaptive perfectionism should be targeted among European Americans.