Parenting is a tough job and it only gets tougher when your kids hit their teen years. Parents find themselves faced with a whole host of new behavioral issues, such as sneaking out of the house. At the same time, you'll likely find that the discipline methods you used when your child was younger aren't effective anymore. When discipling your teen -- for sneaking out or anything else -- try to keep all consequences you mete out related, reasonable, respectful and predictable.
Related discipline is discipline which closely relates to what your teen has done wrong. It is useful because it is easy for your teen to understand that the consequence fits the behavior. When a teen sneaks out, he is taking liberties with privileges that you have not allowed him. One way to provide a related consequence is to further scale back the privileges your teen normally has. Another related consequence would be to insist that your teen leave his bedroom door open -- or even removing it -- so you can more easily check on him until he has rebuilt trust. Your teen should lose some degree of privacy if he wasn't trustworthy with the privacy he had been granted.
When discipling a teen, it's important to realize that you're dealing with someone who will be an adult in a few short years. Taking away privileges and responsibilities long-term denies your teen the opportunity to experience the independence he will need when he is on his own. Make sure that the discipline you impose is reasonable given your teen's behavior. An example of reasonable discipline for a teen who sneaks out to be with her boyfriend would be refusing to let her go out or receive calls from him for a specified amount of time. By contrast, grounding her to her room for six months and never allowing her to date again would be unreasonable.
Ideally, the discipline you impose on your teen for sneaking out should communicate something deeper than the fact that you are angry or disappointed that he has broken your rules. Your discipline should convey the fact that you care about him and are concerned for him. Avoid punishments that needlessly shame or embarrass your teen in front of others. Not only are they ineffective, but they can cause long-term damage to your relationship with him. Respectful punishments address the behavior while still affirming your love and concern for your teen.
The best time to determine and communicate consequences for a teen is before the misbehavior occurs. Your teen is old enough to understand that actions have consequences. If he knows the consequences for sneaking out ahead of time, he should have nothing to complain about when you impose them. If your teen is relatively mature, you might even consider gaining his input on what the consequences for sneaking out should be. Ask your teen to place himself in your shoes and think about what he would do if his son or daughter snuck out at night.