Employers who hire employees “at will” are not required by law to give advance notice of the dismissal of an employee.
Giving notice to employees about leaving helps the company maintain a positive image, especially if they communicate the reasons for leaving.
There is a law on the books, the WARN Act, that requires employers (those with 100 or more employees) who are planning mass layoffs or have plans to close a factory or plant to give their employees 60 days’ notice.