How much can an employer disclose to other parties about your reason for being terminated?

1) An employer is not required to notify employees of the reason for termination, unless there is an employment contract which in one way or another (e.g. by limiting the grounds for termination; the employer would have to show that one of the reasons for termination occured) requires this. Otherwise, without a contract, you are an employee at will and may be fired at any time, without any explanation.

2) Unless there is some nondisclosure or confidentiality agreement or clause (such as might be part of a seperation and release agreement or employment contract), the employer may tell anyone it wishes about the reason(s) for your termination; there is nothing inherently private or protectible about the reasons for termination, so any limitations on the employer's ability to disclose this must be based in contract.

3) The employer may not defame you, or make untrue statements of fact about you to third parties which damages your reputation. True facts are not defamation, no matter how damaging; and opinions (e.g. "John/Jane Doe is lazy and rude") are not defamation, either. But untrue negative facts (e.g. saying that you were fired for theft, when you did not steal) could be defamation, and if you have been defamed, you might have a legal claim or cause of action.