BSD licenses represent a family of permissive free software licences. The original was used for the Berkeley Software Distribution, a Unix-like operating system for which the license is named. The original owners of BSD were the Regents of the University of California because BSD was first written at the University of California, Berkeley. The first version of the license was revised, and the resulting licenses are more properly called modified BSD licenses. Permissive licenses, sometimes with important differences pertaining to license compatibility, are referred to as "BSD-style licenses". Several BSD-like licenses, including the New BSD license, have been vetted by the Open Source Initiative as meeting their definition of open source.

The licenses have few restrictions compared to other free software licenses such as the GNU General Public License or even the default restrictions provided by copyright, putting it relatively closer to the public domain. The BSD licenses have been referred to as copycenter, as a comparison to standard copyright and copyleft free software: "Take it down to the copy center and make as many copies as you want."