胡克定律（Hooke's law），又译为虎克定律，是力学弹性理论中的一条基本定律，表述为：固体材料受力之后，材料中的应力与应变（单位变形量）之间成线性关系。满足胡克定律的材料称为线弹性或胡克型（英文Hookean）材料。

从物理的角度看，胡克定律源于多数固体（或孤立分子）内部的原子在无外载作用下处于稳定平衡的状态。

许多实际材料，如一根长度为L、横截面积A的棱柱形棒，在力学上都可以用胡克定律来模拟——其单位伸长（或缩减）量 （应变）在常系数E（称为弹性模量）下，与拉（或压）应力 σ 成正比例，即：

或

Hooke's law is a principle of physics that states that the force F needed to extend or compress a spring by some distance X is proportional to that distance. That is: F = kX, where k is a constant factor characteristic of the spring: its stiffness, and X is small compared to the total possible deformation of the spring. The law is named after 17th-century British physicist Robert Hooke. He first stated the law in 1660 as a Latin anagram. He published the solution of his anagram in 1678 as: ut tensio, sic vis ("as the extension, so the force" or "the extension is proportional to the force").