Abstract—The current article has been focused on the mucoadhesive drug delivery system may be designed to enable prolonged retention at the site of application, providing a controlled rate of drug release for improved therapeutic outcome. Mucoadhesion is commonly defined as the adhesion between two materials, at least one of which is a mucosal surface. Application of dosage forms to mucosal surfaces may be of benefit to drug molecules not amenable to the oral route, such as those that undergo acid degradation or extensive first-pass metabolism. The mucoadhesive ability of a dosage form is dependent upon a variety of factors, including the nature of the mucosal tissue and the physicochemical properties of the polymeric formulation. This review article aims to provide an overview of the various aspects of mucoadhesion, mucoadhesive materials, factors affecting mucoadhesion, evaluating methods, and finally various mucoadhesive drug delivery systems (buccal, nasal, ocular, gastro, vaginal, and rectal) based on literatures were reported so far.