凝胶电泳（英语：Gel electrophoresis）或称胶体电泳，是一种用于大分子（如DNA、RNA、蛋白质）以及其碎片的分离、分析技术。该技术被科学工作者用于分离具有不同物理性质（大小、电荷、等电点）的分子。凝胶电泳通常用于分析用途，但也可以作为预处理技术，在进行质谱、聚合酶链式反应、克隆、DNA测序或者免疫印迹等检测之前，进行分子的纯化。

凝胶电泳在用于分离核酸分子时，带有负电荷的核酸分子在外加电场的作用下穿过凝胶组成的网格。由于较小的分子更容易通过网孔，较小的分子凝胶基质中穿行地更快，并且可以移动得更远。这与分子筛的现象类似。

Gel electrophoresis is a method for separation and analysis of macromolecules (DNA, RNA and proteins) and their fragments, based on their size and charge. It is used in clinical chemistry to separate proteins by charge and/or size (IEF agarose, essentially size independent) and in biochemistry and molecular biology to separate a mixed population of DNA and RNA fragments by length, to estimate the size of DNA and RNA fragments or to separate proteins by charge.