买方垄断（英语：Monopsony），也称独买、买方独占，经济学术语，指在一个市场上只存在一个买者而有许多卖者的情况。由此形成的市场称为买方垄断市场，该市场上的购买量由买方的边际价值和边际费用决定。这个术语由英国经济学家琼·罗宾逊（Joan Violet Robinson）在1933年的著作《不完全竞争经济学》（The Economics of Imperfect Competition）中提出，作为一种不完全竞争的状况，但在现实中不常见。

In economics, a monopsony (from Ancient Greek μόνος (mónos) "single" + ὀψωνία (opsōnía) "purchase") is a market structure in which only one buyer interacts with many would-be sellers of a particular product. In microeconomic theory of monopsony, a single entity is assumed to have market power over terms of offer to its sellers, as the only purchaser of a good or service, much in the same manner that a monopolist can influence the price for its buyers in a monopoly, in which only one seller faces many buyers.