长鞭效应（Bullwhip effect）是一种在需求预测驱动的销售渠道中被观察到的现象。

此理论最早在1961年由J Forrester在Industrial Dynamics中提出。在一般的商业活动中，客户的需求总是不稳定的，企业总是需要通过预测客户的需求来优化库存与其他资源的配置。而预测是创建在统计基础上的，一般来说是不可能完全精确的，所以企业在运营中常常会保留一些额外的库存作为安全库存（safety stock）。在供应链中，从下游到上游，从终端客户到原始供应商，每一个组成部分所需求的安全库存将会越来越多。在需求升高的时期，下游的企业将会增加从上游订货的数量，在需求降低的时期，下游的企业将会减少或者停止订货。而这种需求量的变化会随着供应链上溯而被放大。这种信息扭曲的放大作用在图形显示上很像一根甩起的长鞭，因此被形象地称为长鞭效应。最下游的客户端相当于鞭子的根部，而最上游的供应商端相当于鞭子的梢部，在根部的一端只要有一个轻微的抖动，传递到末梢端就会出现很大的波动。在供应链上，这种效应越往上游，变化就越大，距终端客户越远，影响就越大。

The bullwhip effect is a distribution channel phenomenon in which forecasts yield supply chain inefficiencies. It refers to increasing swings in inventory in response to shifts in customer demand as you move further up the supply chain. The concept first appeared in Jay Forrester's Industrial Dynamics (1961) and thus it is also known as the Forrester effect. The bullwhip effect was named for the way the amplitude of a whip increases down its length. The further from the originating signal, the greater the distortion of the wave pattern. In a similar manner, forecast accuracy decreases as move upstream along the supply chain. For example, many consumer goods have fairly consistent consumption at retail. But this signal becomes more chaotic and unpredictable as you move away from consumer purchasing behavior.