KPCS is the official acronym for the Kimberley Process Certification Scheme, the inter-governmental regime adopted in 2003 to prevent rough conflict diamonds from entering the legitimate international supply chain. The scheme is named for the South African town of Kimberley, where producing-country governments first met in May 2000 to negotiate a response to public concern about diamonds financing civil wars in Angola, Sierra Leone and the Democratic Republic of the Congo.

The KPCS is a treaty-like arrangement endorsed by United Nations General Assembly resolutions but operating on a consensus basis among its Participants, who currently number more than 80 governments and the European Union (acting on behalf of member states). Each Participant agrees to issue a tamper-resistant certificate (a KP Certificate) for every export shipment of rough diamonds, to refuse imports without such a certificate, and to publish production and trade statistics for reconciliation by the KP Statistics Working Group.

The scheme covers rough diamonds only. Polished stones are addressed indirectly through the World Diamond Council's voluntary System of Warranties, which carries an equivalent statement of conflict-free origin through each transaction in the polished pipeline. KPCS, KP and Kimberley Process are used interchangeably in the trade, although KPCS appears most often in formal documents and government publications, while KP dominates everyday correspondence.