Audacity is a free and open-source digital audio editor and recording application software, available for Windows, macOS, Linux, and other Unix-like operating systems. Audacity was started in the fall of 1999 by Dominic Mazzoni and Roger Dannenberg at Carnegie Mellon University and was released on May 28, 2000. As of October 24, 2020, it is the most popular download from FossHub, with over one hundred million downloads since March 2015. Previously, downloads were served from Google Code and SourceForge, with a combined total in excess of 120 million downloads. Audacity won the SourceForge 2007 and 2009 Community Choice Award for Best Project for Multimedia. Audacity is licensed under GPLv2 or any later version.

Audacity is used for a large variety of audio related purposes, ranging from audio analysis for research, editing podcasts, recording speech and music, digitising vinyl and cassettes, changing audio formats, mixing and master, applying audio effects, batch processing audio, and many more audio editing tasks. It has a long history of open-source contributions and continues to be actively developed by both full-time and part time developers.