This review provides an overview of the vast gastrointestinal tract complications of diabetes that can occur from the mouth to the anus. The presentation, diagnosis, and management of gastrointestinal disorders, ranging from gastroparesis, celiac disease, and bacterial overgrowth to nonalcoholic fatty liver disease, are reviewed to heighten awareness. When managing care of patients with diabetes, one should keep in mind the potential gastrointestinal complications, as well as the frequent disorders that are not related to diabetes.