In your company, are you allowed to talk to your supervisor's supervisor?

while it is not normally against company policies, most companies have a tiered management structure, and you are expected to attempt to resolve all issues thru the chain of command, ie you tell your immediate supervisor, who will speak with his boss and so on...

you should go to your immediate supervisor first, as it is his job to supervise you... if you go straight to the next in charge he may ask if you have attempted to resolve it with your supervisor. He may be too busy to deal with your request personally, or may be upset that you did not follow proper channels, or he may welcome speaking with you... however either way, your supervisor will not be happy you went over his head...

unless you absolutely have to it is not recommended, it can cause tension between you and your immediate supervisor(s)

Most companies will not disallow someone to speak to their supervisor's supervisor. The Human Resources department will most often espouse an "open door policy" wherein individuals can express concerns with superiors, including the supervisor's supervisor, HR, or other managers and executives. This is important.

That said, the immediate supervisor may not like an employee showing disregard for the "chain of command." And the employee needs to have a good relationship with the manager. So if the issue isn't significant, the employee would be wise to not go to the supervisor's supervisor for casual issues.

If there is intimidation, harassment, inappropriate behavior, unfairness, or some other unacceptable condition, you should contact HR and/or your supervisor's supervisor.