The current review article describe on the principles of mucoadhesive buccal drug delivery systems based on adhesion to biological surfaces that are covered by mucus. The delivery of drugs through the buccal mucosa has attracted and numerous approaches, both conventional and complex, have been developed in an attempt to deliver a variety of pharmaceutical compounds via the buccal route. Buccal delivery involves the administration of the desired drug through the buccal mucosal membrane lining of the oral cavity. Buccal transmucosal delivery helps to bypass first- pass metabolism by allowing direct access to the systemic circulation, maintaining the drug concentration between the effective and toxic levels, inhibiting the dilution of the drug in the body fluids, and allowing targeting and localization of a drug at a specific site. It is a complex phenomenon which involves wetting or swelling and interpenetration of polymer chains, it can be of Matrix or Reservoir types. This article aims at reviewing the numerous techniques that has been designed till date for optimizing novel transmucosal buccal drug delivery system.