Counterintelligence Service

Counterintelligence Service may refer to:


 * Counterintelligence Corps (United States Army) (1917-1961)
 * KOS (Yugoslavia), the Kontraobavještajna služba, the counterintelligence service of the Yugoslav People's Army
 * MI5, the United Kingdom's internal counterintelligence and security agency
 * Internal Counter-Intelligence Service, fictional British military organization from the UNIT audio plays by Big Finish