亮氨酸拉链（英语：leucine zipper，亦称为亮氨酸剪刀）是蛋白质中一种常见的三维结构模体，常见于许多转录因子的DNA结合结构域，因此涉及基因的表达调控。亮氨酸拉链在真核生物和原核生物的蛋白中都有发现，但以真核生物居多。

亮氨酸拉链是一种作为二聚体化结构域的超二级结构，且使相互平行的α-螺旋之间产生粘附力。一个亮氨酸拉链包含了多个亮氨酸残基，通常每七个氨基酸残基就出现一次，这形成了一条两性的α-螺旋，疏水区只在其中一侧。这个疏水区提供了二聚化的区域，使得基序可以像“拉链”一样拉起来。此外，疏水亮氨酸区域对于其结合到DNA是不可或缺的。

A leucine zipper, aka leucine scissors, is a common three-dimensional structural motif in proteins. They were first described by Landschulz and collaborators in 1988 when they found that an enhancer binding protein had a very characteristic 30-amino acid segment and the display of these amino acid sequences on an idealized alpha helix revealed a periodic repetition of leucine residues at every seventh position over a distance covering eight helical turns. The polypeptide segments containing these periodic arrays of leucine residues were proposed to exist in an alpha-helical conformation and the leucine side chains from one alpha helix interdigitate with those from the alpha helix of a second polypeptide, facilitating dimerization.