CIK or Cik may refer to:
Organisations CIK Telecom, a Canadian telecommunications company Euroclear Belgium, a Belgian central securities depository formerly known by the acronym CIK (for Caisse Interprofessionnelle de Dépôts et de Virements de Titres / Interprofessionele Effectendeposito- en Girokas) Confederazione Italiana Kendo, a Kendo Federation in Italy Commission Internationale de Karting, the primary international sanctioning body for Kart racing
Places Čik, a river in northern Serbia Chalkyitsik Airport (IATA: CIK), an airport in Chalkyitsik, Alaska
Science and technology Cytokine-induced killer cell, a subset of natural killer T cells Crypto Ignition Key, or KSD-64, a security token developed by the U.S. National Security Agency
Other uses Central Index Key, a number assigned by the US Securities and Exchange Commission to identify financial filings Chiksana railway station (station code CIK), a railway station in Chak Baltikari, Uttar Pradesh, India