The human esophagus is lined by a non-keratinizing, stratified squamous epithelium whose apical cell membranes and intercellular junctional complexes form a barrier against the influx of luminal content. The barrier helps to reduce exposure of surface cells to changes in osmolality, which occurs frequently within the esophageal lumen. Histologically, the esophageal epithelium consists of two zones, the basal and differentiated zones. Cellular proliferation is limited to the basal zone, and the cells migrate from this area towards the esophageal lumen. Migration involves several processes, such as the initiation of differentiation and the sequential expression of differentiation markers. Human esophageal epithelial cells are an excellent tools to study esophageal epithelium physiology and also the mechanisms of esophageal carcinogenesis.