The most important thing you can do if you find your child cheating is to act immediately. It's important that a child find out right away that he hasn't gotten away with anything. Here's an age-by-age guide to handling your child's cheating:
Under age 5
Respond immediately, but in a light manner -- even making a joke of the situation. This will let her know that cheating is something she can't get away with without punishing her for doing something that she probably didn't know was wrong in the first place.
Ages 5 and up
With children this age, you should be a bit stricter in your response. But avoid excessive punishment. Instead, sit your child down and ask her why she cheated. Discuss the seriousness of what she did and ask her about the kinds of stresses and pressures that may have motivated her to cheat.
If your child is 8 or older
If a child this age continues to have a chronic cheating problem or gets labeled a "cheater" at school, he may need further help. Often, cheating at this age is a symptom of an internal emotional struggle or peer pressure. Seek assistance from a mental health counselor or a child guidance clinic.