In California, employers do not have to give at-will employees a reason for termination because employers can fire at-will employees for no reason at all. In fact, it is probably a good practice for employers to not give employees reasons for firing because it reduces employees’ opportunities to challenge the reason. Also, employers who give employees a reason may find themselves locked into that reason which may not be good enough to save them from liability in employees’ future lawsuits.
On the other hand, an employee who is not at-will, meaning an employee who has a contract for a specified duration of time, would have a right to know the reason for termination.This type of employee has this right because an employer can only fire an employee with a contract for a specific duration when the employer has good cause to cut the duration of the contract short.Hence, the employer would have to communicate the good cause to the fired employee.
(See Link(s): Labor Code Section 2922)