Today, Ionic liquids have been very well recognized in the field of corrosion as efficient inhibitors of various metals and alloys, owing to their environmentally friendly nature and strong adsorption properties. The alteration in the cationic part of the ionic liquids increases the electron donation capacity which makes their interaction feasible with the metal surface in the aggressive medium. This attraction leads to the protection of the metal surface from dissolution. The dissociation behavior of ionic liquid indicates the mode of adsorption on the surface of the metal. The adsorption of ionic liquid is also dependent on its chemical structure, the nature of a charge on the metal surface, and many other factors. This chapter gives an overview of factors governing the adsorption of inhibitors on the metal surface, mechanistic details, etc., with significant illustrations as documented in the literature.