The oral mucosa resembles intestinal mucosa because it has epithelial cells with high turn over rate and the mucosa is constantly bathed in fluid. It is also similar to skin because it has a stratified epithelium which in many sites is keratinised. To meet its functions in the masticatory process and as the barrier and protection aid in the immune system of the oral cavity, there are three types of oral mucosa: masticatory mucosa which is well developed for resisting high mechanical stress, lining mucosa which provides flexibility and specialised mucosa which contains the gustatory receptors. Basically the oral mucosa cosists of the oral epithelium and the lamina propria which is a connective tissue layer of variable width beneath the epithelium. In some regions a submucosa layer binds the mucosa to the underlying tissues. This paper would describes the regional variation of the oral mucosa microscopic structure with an introductory overview on the macroscopic structure of the oral cavity region covered by the mucosa.