Shareware (sometimes also called trialware or demoware) is software distributed for free, on a trial basis. In most cases, shareware is limited in functionality, possible time of use, or availability.

The goal of shareware is to provide potential customers with a sample of the final software to try out before the customer decides to buy it.

Shareware was at one time, for example, the Internet browser Opera, the free version of which was limited by display advertising. The paid version of the browser then had no advertising bar. A well-known example of shareware was the legendary 1993 computer game Doom.

If the shareware is not limited in functionality, but limited in time, it will stop working when the time limit expires, or it may work in an even more limited mode. Thereafter, the purchase of a license is required if the user wishes to continue using the software.

Shareware used to be distributed via floppy disks and CDs, but nowadays it is almost exclusively distributed via the Internet.