In California, "Wrongful Termination" is a legal term that refers to an illegal termination of employment. Many terminations people think of as "wrongful" are not in fact illegal. In California, employment is "at will." This means an employer can fire its employee for almost no reason at all. There are three general exceptions to this rule: First, where an employer terminates an employee for a discriminatory purpose; second, where an employer terminates an employee in breach of an employment contract; finally, where an employer terminates an employee for taking some protected legal action.
Employees cannot be discriminated against by their employer on the basis of age, race, sex, national origin, sexual orientation, religion, disability, and a variety of other reasons. If an employee is terminated for one of these reasons, it is against the law, and the employee can sue for "wrongful termination."
If any employee has an employment contract with his or her employer, it is likely that the employer must find "just cause" to terminate the employee. If an employee is terminated in violation of his or her employment contract, it is against the law, and the employee can sue for "breach of contract."