List of contract killers and hitmen

This article contains a list of contract killers, both living and deceased, sorted by the country in which they engaged in said crimes.
The practice of contract killing involves a person who is paid to kill one or more individuals. As implied by the name, the contract killer typically does such solely for the purpose of profit and often lacks any personal connection to their intended target. A hitman, on the other hand, is a term that is often synonymous with contract killer although it can also be used to denote a criminal who frequently carries out a targeted killing on behalf of an organized crime syndicate with which they are affiliated. Furthermore, the title of enforcer can also be interchangeable with the latter of the two as it is generally associated with gangsters even though not all gang enforcers necessarily resort to homicide on a regular basis or even at all.
Persons who have only carried out an assassination-style murder at the behest of their own motivation, without having either a criminal background, or links to the criminal underworld or other such groups, do not qualify as hitmen. They are not to be included in this list, nor are assassins who perform killings under the discretion of an official government unless they are purposely done in extrajudicial manner.