NCIS season 20

The twentieth season of the American police procedural television series NCIS premiered on September 19, 2022 on CBS during the 2022–23 television season, and concluded on May 22, 2023. This is the first season to not credit Mark Harmon who portrayed Leroy Jethro Gibbs since the show's first season, and the last to feature David McCallum prior to his death on September 25, 2023. This season includes the 450th episode of the series. The season contained 22 episodes.

Premise
NCIS revolves around a fictional team of special agents from the Naval Criminal Investigative Service, which conducts criminal investigations involving the United States Navy and Marine Corps. Based at the Washington Navy Yard in Washington, D.C., the NCIS team is led by Supervisory Special Agent Alden Parker, an ex-FBI Special Agent and a skilled investigator.

Main

 * Sean Murray as Timothy McGee, NCIS Senior Special Agent, second in command of MCRT, Acting Director of NCIS
 * Wilmer Valderrama as Nick Torres, NCIS Special Agent
 * Katrina Law as Jessica Knight, NCIS Special Agent
 * Brian Dietzen as Dr. Jimmy Palmer, Chief Medical Examiner for NCIS
 * Diona Reasonover as Kasie Hines, Forensic Specialist for NCIS
 * David McCallum as Dr. Donald "Ducky" Mallard, NCIS Historian and former Chief Medical Examiner
 * Rocky Carroll as Leon Vance, NCIS Director
 * Gary Cole as Alden Parker, Supervisory Special Agent (SSA) of the Major Case Response Team (MCRT) assigned to Washington's Navy Yard, former FBI Special Agent turned NCIS's agent

Notable guests

 * Joe Spano as Tobias Fornell, Private Detective and former FBI Senior Special Agent
 * Teri Polo as Vivian Kolchak, Alden Parker’s ex-wife and DOD paranormal investigator
 * Laura San Giacomo as Dr. Grace Confalone, psychotherapist
 * Carolyn Hennesy as Tara Flynn, the Secretary of the Navy
 * Patrick Labyorteaux as Olev Kozlov (previously appeared as Bud Roberts)
 * David Blue as Charlie Samuels
 * Lilan Bowden as Robin Knight, Jessica Knight's sister
 * Margo Harshman as Delilah Fielding-McGee, DoD Intelligence Analyst and McGee's wife
 * Juliette Goglia as Viktoria Valkov/Evelyn Shaw, Russian spy, Yuri's sister and Kostya's daughter
 * Gregg Binkley as Bob Stivers
 * Robert Picardo as Retired Marine Gunnery Sergeant Dale Harding
 * Rachel Ticotin as Joy Sullivan Aaronson, Alden Parker's first love
 * Zane Holtz as Dale Sawyer, NCIS Special Agent
 * Tania Raymonde as Chloe Marlene
 * Francis Xavier McCarthy as Roman Parker, Alden Parker's father
 * Michael Patrick Thornton as Jeremy Brighton, author, podcaster and online parenting coach for wheelchair users
 * Brigid Brannagh as Constance Miller, US senator
 * Scott Lawrence as DEA Agent Raymond Frank (previously appeared as Sturgis Turner in JAG from 2001 to 2005)
 * James Snyder as Dr. Miles Bauer
 * Ilia Volok as Kostya Valkov, Viktoria and Yuri's father

NCIS: Hawaiʻi

 * Vanessa Lachey as Jane Tennant, NCIS Special Agent in Charge
 * Jason Antoon as Ernie Malik, NCIS cyber intelligence specialist
 * Noah Mills as Jesse Boone, NCIS second-in-command

NCIS: Los Angeles

 * Chris O'Donnell as Grisha "G." Callen, NCIS Supervisory Special Agent
 * LL Cool J as Sam Hanna, NCIS Senior Field Agent, Second in Command

Development
On March 31, 2022, NCIS was renewed for a twentieth season, which premiered on September 19, 2022.