The Central Intelligence Agency is an agency involved with the intelligence of the United States of America.
The CIA has occasionally (usually grudgingly) assisted with NCIS investigations.
- Jack Canton- A rogue CIA agent who appeared in Marine Down (episode). Died after being caught in a gunfight between himself and NCIS Special Agents Anthony DiNozzo and Caitlin Todd.
- Roy Carver- A Department of Homeland Security official who previously worked for the CIA in 1991.
- Jonas Cobb- A former Navy Lt. who became an assassin for the CIA. Unfortunately, the strain of taking a human life later caused his mind to snap under the pressure and after disappearing, later emerged as a serial killer known as the "Port to Port Killer".
- Ray Cruz- A CIA agent who was also NCIS Special Agent Ziva David's boyfriend for a time.
- Gonzales- Rogue agent Jack Canton's partner who appeared in Marine Down (episode). Died after Canton shot him in the heart.
- Jim Kidwell- A Major in the United States Marine Corps who was also an unofficial CIA agent. Died after being embalmed while he was being held hostage in Colombia.
- Roger Kirkwood- The Director of the CIA who appeared in Semper Fidelis (episode).
- Trent Kort- A CIA agent who serves as a help and hindrance to Gibbs and his team. Later ended up fired by 2015.
- Andrew Kramer- A CIA agent who appeared in A Weak Link (episode).
- Craig Peary- A Major in the United States Marine Corps who like his partner, Jim Kidwell was an unofficial agent for the CIA.