Diabetes mellitus (DM) is a worldwide epidemic, making it a major non-communicable disease of public health concern. DM is a chronic disease affecting various organs of the body, leading to increased morbidity and frequently causing patients to seek medical care. Patients with DM often suffer from gastrointestinal disturbances, indicating the involvement of the gastrointestinal system (GIS). Common effects on the gastrointestinal tract (GIT) include esophageal dysmotility, gastroesophageal reflux disease (GERD), non-alcoholic fatty liver disease (NAFLD), glycogenic hepatopathy, gastroparesis, and enteropathy. Despite the high rates of GIT complications associated with diabetes, they are often under-recognized by physicians, leading to suboptimal treatment and a poor quality of life for patients. This article reviews the GIT manifestations of DM from the esophagus to the anal canal, including their pathophysiology and current management strategies.