In my opinion, anyone who is being assaulted has the right to defend themselves, even if it's at school. Of course, your son would probably get in trouble at school, whether or not you punish him is your choice.In my experience (I was bullied a lot in high school) telling on bullies doesn't do much. The only time a school official will do more than tell the bully to stop is if they are caught in the act. And to be fair, you really can't punish someone for something you didn't see them do. One child's word against another's isn't reliable. I wouldn't give my son a time out just because my daughter said he hit her, you know?Have your son keep his distance from those who are picking on him and talk to his teacher(s) and principal again. Make them understand that your son is being bullied and that you won't allow your son to picked on. Tell them that you will go to the police if the school isn't willing to do anything. Your son has the right to a safe school environment and the police will step in if the school won't.