法拉第笼（英语：Faraday cage）是一个由金属或者良导体形成的笼子。

由于金属的静电等势性，可以有效的屏蔽外电场的干扰。法拉第屏罩无论被加上多高的电压内部也不存在电场。而且由于金属的导电性，即使笼子通过很大的电流，内部的物体通过的电流也微乎其微。在面对电磁波时，可以有效的阻止电磁波的进入。

由于法拉第屏罩的静电屏蔽原理，在汽车、飞机等交通工具中的人是不会被雷击的。同样，也是因为法拉第屏罩的原理，有金属外皮的同轴电缆也可以不受干扰地传播讯号。如果电梯内没有中继器的话，那幺当电梯关上的时候，里面任何电子讯号也收不到。为防止干扰，一些精密仪器需放在笼内才可进行运作或量测。或者也可以再开一个洞，例如金属机身构造的的智能型手机。

A Faraday cage or Faraday shield is an enclosure formed by conductive material or by a mesh of such material, used to block electric fields. Faraday cages are named after the English scientist Michael Faraday, who invented them in 1836.

A Faraday cage operates because an external electrical field causes the electric charges within the cage's conducting material to be distributed such that they cancel the field's effect in the cage's interior. This phenomenon is used to protect sensitive electronic equipment from external radio frequency interference (RFI). Faraday cages are also used to enclose devices that produce RFI, such as radio transmitters, to prevent their radio waves from interfering with other nearby equipment. They are also used to protect people and equipment against actual electric currents such as lightning strikes and electrostatic discharges, since the enclosing cage conducts current around the outside of the enclosed space and none passes through the interior.