IKS was a three-letter acronym that was a common starship prefix in the Klingon Empire. In this capacity, the prefix stood for Imperial Klingon Ship. (DS9: "Sons of Mogh")

Vessels identified with this prefix included the IKS Drovana and the IKS Korinar, (DS9: "Sons of Mogh") the IKS Gr'oth, (DS9: "Trials and Tribble-ations") the IKS Rotarran, (DS9: "Sons and Daughters") the IKS Fek'lhr, and the IKS K'mpec. (DS9: "Image in the Sand", "The Siege of AR-558")

The designation "IKS" and full meaning, "Imperial Klingon Ship", were both introduced in "Sons of Mogh". Prior to this use, it had been established, primarily by Michael Okuda in the Star Trek Encyclopedia, that the standard Klingon starship prefix was "IKC". This belief was based on the translation of communications chatter in Star Trek: The Motion Picture that identifies the lead vessel in the assault on V'ger as the Imperial Klingon Cruiser Amar.