Fungi, both yeasts and filamentous types, can cause infection of different sites in the oral cavity like buccal mucosa, gingiva and tongue. They are also components of the normal oral microbiota. In specific settings like denture usage, immunodeficiency due to HIV infection and inhalational steroid therapy, fungi, especially yeasts can affect different sites of the oral cavity producing different types of lesions. Studying these infections is important since they might lead to complications if left untreated and usually respond quite favourably to correct and timely antifungal treatment.