Kids are affected by quite a few of the new measures.
Newspapers and councils now have the right to name and shame kids who are given anti-social behaviour orders.
The legal age for owning an air gun has now been raised from 14 to 17.
Sixteen and 17-year-olds can now be given on-the-spot fines for offences such as making hoax 999 calls and throwing fireworks.
Home Secretary David Blunkett said: "From today people have new tools in their fight against neighbours from hell, intimidating groups on their streets and potentially lethal firearms."