勒夏特列原理（Le Chatelier's principle）或翻译为吕·乍得里原理，又称平衡移动原理，是一个定性预测化学平衡点的原理，其内容为：

也就是说，对于一个在某一个特定条件下达到平衡的体系，假设这个条件改变，这个平衡就会朝减弱该改变的方向移动。

这个原理只能用来定性判断，不能进行定量计算，不能首先判断平衡是否处于平衡态。

In chemistry, Le Châtelier's principle (pronounced /lə ˈʃɑːtlieɪ/), also called Chatelier's principle or "The Equilibrium Law", can be used to predict the effect of a change in conditions on a chemical equilibrium. The principle is named after Henry Louis Le Châtelier and sometimes Karl Ferdinand Braun who discovered it independently. It can be stated as: