Eosinophilic gastrointestinal disorders (EGIDs) are chronic inflammatory conditions with increasing global prevalence. Self-efficacy is important for patients’ ability to manage chronic disease. We sought to evaluate disease-specific self-efficacy in the EGIDs via a modified version of the Inflammatory Bowel Disease Self-Efficacy Scale (IBD-SES). Ninety-one Participants reported demographic, clinical, and psychosocial variables. The IBD-SES demonstrated excellent reliability and validity in this population. Self-efficacy was higher in men, patients with less severe disease, and those who had consulted a dietitian. The IBD-SES is a useful measure of disease-specific self-efficacy in the EGIDs. Further research is necessary to understand the role of self-efficacy in the management of these illnesses.