At-will employment means that employee can be let got any time, for any reason, as long as the reason is not illegal.  A common phrase is “an employee can be terminated for a good reason, a bad reason, or no reason, just not an illegal reason.”An at-will employee can also quit at any time, for any reason.

At-will employment is different than employment based on contract.  If there is an employment contract in place, the employment relationship is determined by that contract.