A flashlight (or torch in British English) is a hand-held portable electric-powered light source. Usually the light source is a small incandescent light bulb or light-emitting diode (LED). Typical flashlight designs consist of a light source mounted in a reflector, a lens to protect the light source and reflector, a battery or other power source, and a switch.

The invention of the dry cell and miniature incandescent electric light bulbs made the first flashlights possible around 1899. Today flashlights use mostly incandescent lamps or light-emitting diodes and run on disposable or rechargeable batteries. Some are powered by the user turning a crank or shaking the lamp, and some are powered by solar panels.

In addition to the general-purpose hand-held flashlight, many forms have been adapted for special uses. Head or helmet-mounted flashlights designed for miners and campers leave the hands free. Some flashlights can be used underwater or in flammable atmospheres.