Anybody can do anything. It depends on how your company normally acts.
If you are leaving on good terms, and your company pays its debts on time, I don't see why they wouldn't do it for you.
If your company regularly jerks vendors and employees around on payments, then I would anticipate them to do the same to you.
If you are worried about them jerking you around I would consult with an attorney, show the attorney your contract, and retain evidence that you earned your bonus until you get the bonus.
There's no pat answer to this question. What does your handbook say about bonuses, if anything? Are there any memos floating around that indicate that the bonus is a formal part of the compensation package? Is the bonus earned, or is it discretionary? Is the amount based on a formula that applies to everyone? Does company policy require you to be an employee at the end of the accounting period or does it require you to be an employee on the date the bonus is due? These, and other factors, need to be taken into consideration. If they withhold the bonus, speak to an experience employment lawyer and be prepared to answer these and other questions. Good luck.
A response to a question posted on Avvo is not intended to create an attorney-client relationship. It is informational only. Allan E. Richardson, Esq. firstname.lastname@example.org Richardson, Galella & Austermuhl 142 Emerson ST., Woodbury, NJ 08096 856-579-7045.