The Lieutenant is an American television series, the first created by Gene Roddenberry. It aired on NBC on Saturday evenings in the 1963–1964 television schedule. It was produced by Arena Productions, one of Metro-Goldwyn-Mayer's most successful in-house production companies of the 1960s. Situated at Camp Pendleton, Southern California, the West Coast base of the U.S. Marine Corps, The Lieutenant focuses on the men of the Corps in peacetime with a Cold War backdrop. The title character is Second Lieutenant William Tiberius Rice, a rifle platoon leader and one of the training instructors at Camp Pendleton. An hour-long drama, The Lieutenant explores the lives of enlisted Marines and officers alike.

The series was known for hosting a plethora of stars and guest stars who would later appear in Roddenberry's more well known work, Star Trek. Rice himself—whose middle name was also shared by the character James T. Kirk—was played by Gary Lockwood, who appeared in the second Star Trek pilot "Where No Man Has Gone Before". Majel Barrett, Leonard Nimoy, Nichelle Nichols, and Walter Koenig all appeared as guest stars, along with Ricardo Montalbán—famous for his portrayal of Khan Noonien Singh—and Paul Comi, from the Star Trek episode "Balance of Terror". Several other prominent stars appear in various other episodes, such as Rip Torn playing a drill instructor, Ted Knight playing a yeoman, veteran actor James Gregory (another Star Trek guest star, from the episode Dagger of the Mind) as a senior Marine NCO, Alice star Vic Tayback as a Marine Corps sentry, and veteran character actor Denver Pyle—later internationally known as Uncle Jesse from The Dukes of Hazzard—appeared in the series as a Marine Corps major.

The series was released on DVD in two half-season sets by the Warner Archive Collection on August 14, 2012.