This lecture focus to presentation on Monopoly Market. Here presented two major functions of monopoly they are: single seller for a product with no close substitutes and barriers to entry. Under the barriers to entry, there are three functions: economies of scale, actions by firms and actions by government. Generally Monopolies created by government action, like, patents and copyrights, government created franchises and licensing. Finally this lecture explain on Price elasticity and MR, Average revenue, Zero-profit monopolist and Regulation of natural monopoly.