NCIS is a media franchise of American television programs originally created by Donald P. Bellisario and currently broadcast on CBS, all of which deal with military related criminal investigations based on the Naval Criminal Investigative Service of the United States Department of the Navy, which includes the United States Navy and the United States Marine Corps.

NCIS is an American military police procedural television series and the first installment within the NCIS media franchise. The series revolves around a fictional team of special agents from the Naval Criminal Investigative Service (NCIS), combining elements of the military drama and police procedural genres with comedy. The concept and characters were initially introduced with two episodes of the CBS series JAG ; as a spin-off from JAG, the series premiered on September 23, 2003, on CBS. To date, it has entered into the 21st full season and has gone into broadcast syndication on the USA Network. Donald P. Bellisario and Don McGill are co-creators and executive producers of the premiere member of the NCIS franchise. As of 2022, NCIS is the third-longest-running scripted, live-action U.S. prime-time TV series currently airing, surpassed only by Law & Order: Special Victims Unit (1999–present) and Law & Order ; it is the seventh-longest-running scripted U.S. prime-time TV series overall.