Thin client is used to describe a type of client/server computing in which applications are run, and data is stored, on the server rather than on the client. Because the applications are executed on the server, they do not require client-resident installation, although the graphical user interface and some application logic may be rendered to the client.

A common misperception is that a thin-client application requires the use of a thin-client device (i.e., a stripped-down desktop machine that costs less to buy and maintain than a regular PC). However, while thin-client applications enable such devices to be used, they do not require it. In fact, more than 85% of devices used to display thin-client Windows applications are regular PCs, typically configured with both “fat-client” applications and access to thin-client ones.