蛋白质电泳（英语：Protein electrophoresis）是根据蛋白质带电量或分子量的大小把不同的蛋白质分开，起到分离纯化的效果。根据带电量分离的叫等电点电泳(二维电泳)，根据分子量分的是用十二烷基硫酸钠聚丙烯酰胺凝胶电泳。后者的运用较广泛，与转膜技术，抗原抗体反应，和成像技术合起来就是分子生物学实验室常用的western-blotting。

Protein electrophoresis is a method for analysing the proteins in a fluid or an extract. The electrophoresis may be performed with a small volume of sample in a number of alternative ways with or without a supporting medium: SDS polyacrylamide gel electrophoresis (in short: gel electrophoresis, PAGE, or SDS-electrophoresis), free-flow electrophoresis, electrofocusing, isotachophoresis, affinity electrophoresis, immunoelectrophoresis, counterelectrophoresis, and capillary electrophoresis. Each method has many variations with individual advantages and limitations. Gel electrophoresis is often performed in combination with electroblotting immunoblotting to give additional information about a specific protein. Because of practical limitations, protein electrophoresis is generally not suited as a preparative method.