Repeal is called, in Law, the procedure through which a regulatory provision, whether of the rank of law or lower, is rendered ineffective. Repeal is, therefore, the action contrary to promulgation.

In general, it can be said that the legislative branch or the agencies, in charge of making changes to laws or regulations, have the power to promulgate and finalize them. Therefore, the legislative branch can promulgate and repeal regulations with the status of law, just as the executive branch can promulgate and repeal regulations with the status of regulations.

However, in some legal systems there also exists the figure of the negative legislator, which consists of a body that has the capacity to repeal norms, but not to promulgate them. It would be the case of a Constitutional Court with respect to those laws that it believes violate the Constitution in force in the country.

The repeal can be express or tacit.

A United Kingdom law that allows warrantless arrest and detention of suspected terrorists violates rights protected under Brogan v The United Kingdom, a decision of the European Court of Human Rights in which the court reviewed the arrest in Northern Ireland of four people under a 1984 British law that created a special powers derogation from the prohibition against warrantless arrests.[1]​.

Main article: law of the European Union.

From the beginning, European Union (EU) law has allowed limited exceptions to its requirements, "to the extent and for the periods strictly necessary" to achieve the Union's objectives. Article 226 of the Treaty of Rome (1957) allowed such exceptions.

In terms of EU law, a derogation may also involve a member state delaying the implementation of an element of an EU Regulation into its legal system for a set period of time, such as five years, or that a member state has chosen not to enforce a specific provision of a treaty due to internal circumstances (typically a state of emergency).[2]​.