Misuse of Drugs Act 1977

The Misuse of Drugs Act 1977, the Misuse of Drugs Act 1984, Misuse of Drugs Act 2015 and the Criminal Justice (Psychoactive Substances) Act 2010 are the acts of the Oireachtas regulating drugs in Ireland. The acts define the penalties for unlawful production, possession and supply of drugs.

In 2015, section 2(2) of the 1977 act was declared in violation of the Irish constitution by the Court of Appeal over concerns about the separation of powers. Specifically, the court held that the government could not engage in policy making to define what drugs are "dangerous, harmful" or what constitutes "misuse" as this was the exclusive right of the Oireachtas. As a result of this ruling, many drugs in Ireland immediately became legal, including ecstasy, ketamine, and crystal meth. The situation lasted 24 hours before emergency legislation closing the loophole could take effect. In 2016, this decision was overturned again by the Irish Supreme Court in Bederev v Ireland.