电压（英语：Voltage，electric tension或 electric pressure），也称作电势差（electrical potential difference）或电位差，是衡量单位电荷在静电场中由于电势不同所产生的能量差的物理量。此概念与水位高低所造成的「水压」相似。需要指出的是，“电压”一词一般只用于电路当中，“电势差”和“电位差”则普遍应用于一切电现象当中。

电压的国际单位是伏特（V）。1伏特等于对每1库仑的电荷做了1焦耳的功，即。

Voltage, electric potential difference, electric pressure or electric tension (formally denoted ∆V or ∆U, but more often simply as V or U, for instance in the context of Ohm's or Kirchhoff's laws) is the difference in electric potential energy between two points per unit electric charge. The voltage between two points is equal to the work done per unit of charge against a static electric field to move the test charge between two points and is measured in units of volts (a joule per coulomb).