Commercial software is computer software sold for profit; such software represented, until recently, the vast majority of all software used. It is also referred to as shrinkware because software almost always ships in a shrinkwrapped box.

Historically, one of the most important events that have led to the expansion of the retail software market was the Open Letter to Hobbyists by Bill Gates in 1976.

The most famous examples of commercial software are the products offered on the IBM PC and clones in the 1980s and 90s, including famous programs like Lotus 123, Word Perfect and the various parts that make up Microsoft Office. Microsoft Windows is also shrinkware, but is most often pre-installed on the computer.

The rise of the internet has dramatically changed the commercial software market. In the past it was possible that a freeware or shareware product would fill a user's needs, but they might never know about it, the only way to find out about products was in computer stores or magazines. Today the market is much more level, users can find shareware products as easily as commercial. The amount of software being sold in stores has dropped dramatically, and the majority of computer magazines have folded due to decreased advertizing revenue.

Commercial software is most often closed source, and often the intellectual property associated with it is protected by copyrights and patents. The rise of open source software has changed this somewhat, with many vendors releasing some or all of their source code into the public at some level. For instance, Apple Computer's Mac OS X is based on a Mach kernel and associated Unix that has been bundled and released in open source as Darwin. Users are forcing similar changes on Sun Microsystems and Microsoft as well.

See also: proprietary software