Human trafficking is the commerce and trade in the movement or migration of people, legal and illegal, including both legitimate labor activities as well as forced labor. The term is used in a more narrow sense by advocacy groups to mean the recruitment, transportation, harbouring, or receipt of people for the purposes of slavery, prostitution, forced labor (including bonded labor or debt bondage), and servitude.

The UNODC, United Nations Office on Drugs and Crime, defines human trafficking according to Annex II, General Provisions, Article 3, Paragraph (a) of the Protocol to Prevent, Suppress and Punish Trafficking in Persons defines trafficking in persons as the "recruitment, transportation, transfer, harbouring or receipt of persons, by means of the threat or use of force or other forms of coercion, of abduction, of fraud, of deception, of the abuse of power or of a position of vulnerability or of the giving or receiving of payments or benefits to achieve the consent of a person having control over another person, for the purpose of exploitation." The UNODC offers practical help to states, not only helping to draft laws and create comprehensive national anti-trafficking strategies but also assisting with resources to implement them. In March 2009, UNODC launched the Blue Heart Campaign to fight human trafficking, to raise awareness, and to encourage involvement and inspire action.

Human trafficking is the fastest-growing criminal industry in the world, with the total annual revenue for trafficking in persons estimated to be between $5 billion and $9 billion. The Council of Europe states, "People trafficking has reached epidemic proportions over the past decade, with a global annual market of about $42.5 billion."Trafficking victims typically are recruited using coercion, deception, fraud, the abuse of power, or outright abduction.

Exploitation includes forcing people into prostitution or other forms of sexual exploitation, forced labor or services, slavery, or practices similar to slavery and servitude. For children, exploitation may also include forced prostitution, illicit international adoption, trafficking for early marriage, or recruitment as child soldiers, beggars, for sports (such as child camel jockeys or football players), or within certain religious groups.

Human trafficking is by its very nature an international crime that requires a high level of co-operation and collaboration between states if it is to be tackled effectively. The OSCE (Organization for Security and Co-operation in Europe), an ad hoc intergovernmental organization under the United Nations Charter, is one of the leading agencies fighting the problem of human trafficking, with an area of operation that includes North America, Europe, Russia, and Central Asia.