Private military contractors, private military corporations or private military companies (PMCs) are companies that provide armed staff trained in combat, i.e. private military, for other corporations, organizations, individuals and state military forces. The term is also used for the staff of such companies.

When providing services to a State's military they may be described more generally as defense contractors. When working for a State's military the difference in nomenclature seems to be arbitrary, the chief distinction that may be made is that defense contractors supply specialized hardware and the personnel to support and service that hardware, while PMCs supply personnel with specialized skills, which often include combat experience. The 1949, Third Geneva Convention (GCIII) does not recognize the difference between defense contractors and PMCs, it defines a category called supply contractors. If the supply contractor has been issued with a valid identity card from the armed forces which they accompany, they are entitled to be treated as prisoners of war upon capture (GCIII Article 4.1.4). If however the contractor engages in combat, on capture they can be classified as a mercenary under the 1997 Protocol I Additional to the Geneva Conventions (Protocol I) Article 47.c, unless they fall under an exemption to this clause as listed in Article 47. If on capture contractors are found to be mercenaries, they are an unlawful combatant and lose the right to prisoner of war status.

There has been a recent exodus from many special forces across the globe towards these private military corporations. The United Kingdom Special Air Service, the United States Army Special Forces and the Canadian Army's Joint Task Force 2 have been hit particularly hard. Operators are lured by the fact that entry level positions with the various companies can pay up to $100,000 a year, which is 2-3 times more than what an average special forces operator is paid. However, this conventional wisdom has been disputed especially in the United States where GAO research has detected no noticeable exodus.
The site provides links to many of the PMCs' web pages to include Blackwater USA.