Certification
- Argentina:13
- Australia:M (seasons 1-3 and 6, DVD rating)
- Australia:MA15+ (seasons 4 and 5, DVD rating)
- Canada:14A (Manitoba, DVD rating)
- Canada:PG (Nova Scotia, DVD rating)
- Canada:G (Quebec)
- France:10 (some episodes)
- Germany:16 (seasons 1-4, DVD rating)
- Germany:12 (seasons 5 and 6, DVD rating)
- Italy:BA
- Japan:18 (self-applied)
- Netherlands:12
- New Zealand:R13 (season 4)
- New Zealand:M (seasons 1-3)
- Poland:16
- Singapore:PG13 (season 1)
- Spain:12
- United Kingdom:15
- United States:Not Rated