Diabetes mellitus is a chronic non-communicable disease caused by metabolic disorders in the pancreas organ characterized by an increase in blood sugar levels beyond normal. The Southeast Asian region, which includes Indonesia, is ranked 3rd in the world with a prevalence of diabetes mellitus reaching 11.3%. Meanwhile, Indonesia is ranked 7th out of 10 countries with the most diabetes mellitus sufferers, reaching 10.7 people. Diabetes mellitus can manifest into other diseases, one of which is abnormalities in the oral cavity. Common manifestations of diabetes mellitus in the oral cavity include Oral Infection (Candidiasis), Xerostomia, Periodontal Disease, Recurrent Dental Caries, Burning mouth sensation (related to xerostomia), Taste Dysfunction, Oral Mucosa Alteration (Lichen Planus), Poor Oral Wound Healing. This literature review describes the systemic disease of diabetes mellitus, diagnostic investigations and management of oral manifestations of diabetes mellitus. Management of oral manifestations of diabetes mellitus does not only focus on treating diseases in the oral cavity, but it is more important to eliminate etiological factors and avoid predisposing factors.