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The incandescent light bulb or incandescent lamp is a source of artificial light that works by incandescence. An electrical current passes through a thin filament, heating it and causing it to become excited, releasing thermally equilibrated photons in the process. The enclosing glass bulb prevents the oxygen in air from reaching the hot filament, which otherwise would be destroyed rapidly by oxidation.

Incandescent bulbs are also called electric lamps, extending the use of a term applied to the original arc lamps, and in Australia they are commonly called light globes, or more commonly in other English-speaking countries light bulbs. A benefit of the incandescent bulbs is that they can be produced for a wide range of voltages, from just a few volts up to several hundred volts. Because of their relatively poor luminous efficacy, incandescent light bulbs are gradually being replaced in many applications by (compact) fluorescent lights, high-intensity discharge lamps, LEDs, and other devices.

Brazil and Venezuela were the first countries to attempt to phase out the use of incandescent light bulbs in 2005. Australia has announced it will phase out incandescent light bulbs in favor of compact fluorescent lights by 2010. Politicians in other countries have proposed similar measures (see the Proposals to outlaw section). These proposals have met criticism due to perceived shortcomings of CFLs (Compact Fluorescent Lamps) including consumer safety, environmental issues (CFLs contain small amounts of the toxic element mercury), the emission spectrum of fluorescent lamps, slow cold-weather starting, the increased costs of replacement, and the higher cost of dimmable fluorescent lamps.