In economics, a monopsony (from Ancient Greek μόνος (monos) "single" + ὀψωνία (opsōnia) "purchase") is a market form in which only one buyer faces many sellers. It is an example of imperfect competition, similar to a monopoly, in which only one seller faces many buyers. As the only purchaser of a good or service, the "monopsonist" may dictate terms to its suppliers in the same manner that a monopolist controls the market for its buyers.

The term was first introduced by Joan Robinson in her influential book, The Economics of Imperfect Competition. Robinson credits classics scholar Bertrand Hallward of Peterhouse College, Cambridge with coining the term.

The market condition that exists when there is one buyer and seller may be many. We can take example as ITC (Indian Tobacco Corporation) is only one buyer of Tobacco from various farmers (sellers)