Eosinophilic esophagitis (EoE) is a chronic inflammatory and type-2 immune-mediated disorder of the esophagus diagnosed by the presence of esophageal symptoms accompanied by an esophageal eosinophilic infiltrate. The pathogenesis is related to a combination of an intrinsic or acquired esophageal defect, allergen exposure, genetic/epigenetic changes, and a dysregulated immune response. This leads to the infiltration of eosinophils into the esophagus that causes inflammation, remodeling, and eventually fibrosis if not promptly treated. The incidence and prevalence of EoE continues to increase worldwide and it remains a leading cause of dysphagia and food impactions. With improved understanding of EoE pathophysiology and PPI responsiveness, a paradigm shift occurred in 2017 to eliminate a PPI trial from EoE diagnostic criteria. PPIs remain part of the treatment algorithm along with topical corticosteroids, elimination diets, endoscopic dilation, a biologic (dupilumab), and novel therapeutics that continue to be developed. This chapter provides a comprehensive discussion of existing diagnostic and management strategies for EoE.