光生伏打效应（photovoltaic effect），简称为光伏效应，是指暴露在光线下的半导体或半导体与金属组合的部位间产生电势差的现象。光生伏打效应与光电效应密切相关，属内光电效应。在光电效应中，材料吸收了光子的能量产生了一些自由电子溢出表面。而在光生伏打效应中，由于材料内部的不均匀（例如当材料内部形成PN结时）在自建电场的作用下，受到激励的电子和失去电子的空穴向相反方向移动，而形成了正负两极。

光生伏打效应最早于1839年由法国物理学家亚历山大·爱德蒙·贝克勒尔（Alexandre Edmond Becquerel）发现。

The photovoltaic effect is the creation of voltage or electric current in a material upon exposure to light and is a physical and chemical phenomenon.

The photovoltaic effect is closely related to the photoelectric effect. In either case, light is absorbed, causing excitation of an electron or other charge carrier to a higher-energy state. The main distinction is that the term photoelectric effect is now usually used when the electron is ejected out of the material (usually into a vacuum) and photovoltaic effect used when the excited charge carrier is still contained within the material. In either case, an electric potential (or voltage) is produced by the separation of charges, and the light has to have a sufficient energy to overcome the potential barrier for excitation. The physical essence of the difference is usually that photoelectric emission separates the charges by ballistic conduction and photovoltaic emission separates them by diffusion, but one should note that some "hot carrier" photovoltaic device concepts blur even this line of distinction.