Celiac disease is a T-cell-mediated chronic inflammatory enteropathy with an autoimmune component. The highly variable manifestations of celiac disease lead to a broad spectrum of clinical presentations. Celiac disease is common in the United States, with a reported seroprevalence in both adults and children of roughly 1 in 100. Celiac disease is triggered by the ingestion of gluten-containing grains in genetically susceptible persons. The fact that someone may not develop celiac disease until late adulthood despite being on a lifelong gluten-containing diet, argues for the involvement of environmental cofactors. Wheat, and the taxonomically related rye and barley, serve as the environmental trigger in celiac disease patients. Additional environmental factors that may contribute to the development of celiac disease include infant feeding practices and intestinal infections. Treatment of children diagnosed with celiac disease removes the increased cancer risk of enteropathy-related T-cell lymphoma associated with celiac disease in adulthood.