Workers who have an employment relationship governed by a contract called a collective bargaining agreement (CBA) generally are not subject to the employment-at-will doctrine. The CBA is a contract of the employment relationship between the workers, usually represented by a union, and the management of the employer. Workers under a CBA are not subject to the harsh rule of employment-at-will because a common goal for unions in their negotiations with management is to include a just-cause provision in the CBA, which is the governing contract that controls the parameters of the employment relationship. A just-cause clause provides that an employer shall not fire a worker except for just cause—a very good or justifiable reason.

Sometimes workers who do not work at a large plant with a collective bargaining agreement still are not subject to the employment-at-will doctrine because they have signed an employment contract. This means that a worker who has a valid employment contract is often not subject to the employment-at-will doctrine. Rather, the employee is subject to the terms and conditions of the signed contract. Most workers, however, are not protected by a specific contract. If there is not an agreement that serves as the guide to the employer-employee relationship, the default rule in many states is the employment-at-will doctrine.