How long is too to wait punish a 5 year old for lying?
Instead of punishing a child for lying, it is more effective to talk to them about why it is wrong and to help them understand the difference between truth and fiction. You can also set a good example by being honest yourself and by encouraging your child to be honest with you.
If you are concerned about your child's lying, it is important to talk to a pediatrician or mental health professional.