An uninstaller, also called a deinstaller, is a variety of utility software designed to remove other software or parts of it from a computer. It is the opposite of an installer. Uninstallers are useful primarily when software components are installed in multiple directories, or where some software components might be shared between the system being uninstalled and other systems that remain in use.

Generic uninstallers flourished in the 1990s due to the popularity of shared libraries and the constraints of then-current operating systems, especially Microsoft Windows XP. Declining storage costs and increasing capacity subsequently made reclaiming disk space less urgent, while end-user applications have increasingly relied on simpler installation architectures that consolidate all components to facilitate removal.