foobar2000 is a freeware audio player for Windows developed by Peter Pawlowski, a former freelance contractor for Nullsoft. Featuring a minimalist interface, it also boasts many features for metadata support and high-quality audio output. The theoretical maximum sampling rate and bit depth for audio output are both far in excess of the capacities of even professional-grade audio equipment. To maximize the audio fidelity of consumer-grade equipment, it provides noise shaping and dithering. It features a number of official and third-party components which add many additional features. While the core is closed source, the author provides an extensive SDK under the BSD license. Since version 0.9, foobar2000 supports Windows 2000 and later releases only.

The name foobar is derived from the common placeholder name used in computer programming.