Legalization is the process of removing a legal prohibition against something which is currently illegal.

Legalization is a process often applied to what are now regarded as consensual crimes, such as homosexuality, or the consumption of illegal drugs. It should be contrasted with decriminalization, which removes criminal charges from an offence but still has laws and regulations on it.

It can also occur without political upheaval in the repeal of ancient and no longer relevant laws.

In video engineering, "legalization" can refer to the process of applying constraints on a video signal to keep it within the limits required for broadcast.