Winamp is a media player for Windows-based PCs and Android devices, written by Nullsoft, now a subsidiary of AOL. It is proprietary freeware/shareware, multi-format, extensible with plug-ins and skins, and is noted for its graphical sound visualization, playlist, and media library features.

Winamp was developed by Justin Frankel and Dmitry Boldyrev, and its popularity grew quickly, along with the developing trend of MP3 file sharing.