Oral mucosa is an integral part of the oral cavity that attaches the hard tissues and the soft tissues. The structure of the oral mucosa is different in different parts of the oral cavity based on the functional need. The cytokeratins that make up the skeleton of the epithelial cells and the intercellular junctions are unique to the epithelial cells. The presence of taste buds in the papilla of the tongue makes the mucosa of the tongue a specialized mucosa. The permeability of the mucosa helps in drug delivery. The turnover rate of the epithelium of the oral mucosa is much higher than other epithelial tissues. This chapter describes the histology of the oral mucosa with the structural variations and the clinical implications of the oral mucosa.