Extortion is the practice of obtaining benefit through coercion. In most jurisdictions it is likely to constitute a criminal offence; the bulk of this article deals with such cases. Robbery is the simplest and most common form of extortion, although making unfounded threats in order to obtain an unfair business advantage is also a form of extortion.

Extortion is sometimes called the "protection racket" because the racketeers often phrase their demands as payment for "protection" from (real or hypothetical) threats from unspecified other parties; though often, and almost always, such "protection" is simply abstinence of harm from the same party, and such is implied in the "protection" offer. Extortion is commonly practiced by organized crime. In some jurisdictions, actually obtaining the benefit is not required to commit the offense, and making a threat of violence which refers to a requirement of a payment of money or property to halt future violence is sufficient to commit the offense. Exaction refers not only to extortion or the demanding and obtaining of something through force, but additionally, in its formal definition, means the infliction of something such as pain and suffering or making somebody endure something unpleasant.

The term extortion is often used metaphorically to refer to usury or to price-gouging, though neither is legally considered extortion. It is also often used loosely to refer to everyday situations where one person feels indebted against their will, to another, in order to receive an essential service or avoid legal consequences. Neither extortion nor blackmail requires a threat of a criminal act, such as violence, merely a threat used to elicit actions, money, or property from the object of the extortion. Such threats include the filing of reports (true or not) of criminal behavior to the police, revelation of damaging facts (such as pictures of the object of the extortion in a compromising position), etc.

In law extortion can refer to political corruption, such as selling one's office or influence peddling, but in general vocabulary the word usually first brings to mind blackmail or protection rackets. The logical connection between the corruption sense of the word and the other senses is that to demand bribes in one's official capacity is blackmail or racketeering in essence (that is, "you need access to this resource, the government restricts access to it through my office, and I will charge you unfairly and unlawfully for such access"). Extortion is also known as shakedown, and occasionally exaction.