Several fan-favorite characters have left the long-running show NCIS for various reasons. Sasha Alexander, who played Caitlin Todd, left because she didn't have the stamina for the demanding filming schedule. Cote de Pablo, who portrayed Ziva David, left because she felt her character wasn't being written well anymore. Michael Weatherly, who played Tony DiNozzo, left because he wanted a new challenge and to star in his own show.

Pauley Perrette, who portrayed Abby Sciuto, left due to a falling out with Mark Harmon. Emily Wickersham, who played Eleanor Bishop, left for unspecified reasons and announced her pregnancy shortly after. Maria Bello chose not to renew her contract and left the show on good terms. Mark Harmon's character, Leroy Jethro Gibbs, retired from the show, but Harmon will still serve as an executive producer. David McCallum, who played Ducky, retired from his role but still appears on the show in a limited capacity. There are rumors of returns for Cote de Pablo and Michael Weatherly in future seasons.