Legal Question in Employment Law in Ohio

This may very well depend on what you said and how you said it on facebook. Generally, employers can fire you for any or no reason at all, as you know. If you are just insulting a boss, then that could justify them firing you. If you posted it to facebook during work, that could be grounds to fire you. However, if you posted about working conditions in order to express to other co-workers your feelings about them, and to get them to talk about the same with you, that might be protected as "concerted activity" under the National Labor Relations Act. You should speak with a labor law attorney in your area to find out if you have a good or bad claim, and what you can do if you were terminated for this. In the meantime, if you like your job and don't want to lose it, do you want to push the issue?