The Esc key is a key labeled Esc or Escape that is used to generate the ASCII Escape character (Control-[, ASCII code 27 in decimal), the character code traditionally used to initiate an escape sequence. As the typical computer user is no longer concerned with the details of controlling their computer's peripherals, the task escape sequences were designed for, the escape key was appropriated by application programmers, most often to mean Stop. This use continues today in Microsoft Windows's use of escape as a shortcut in dialog boxes for No, Quit, Exit, Cancel, or Abort.

A common application today of the Esc key is as a shortcut key for the Stop button in many web browsers.

On machines running Microsoft Windows, prior to the implementation of the Windows key on keyboards, the typical practice for invoking the "start" button was to hold down the control key and press escape. This process still works in Windows XP and Windows Vista.

In Mac OS X, one common use for the Esc key, used in combination with the Command key, is switching to Front Row. Additionally, it's indicated as a circle with an arrow through it. (U+238B, ⎋)