"A Private Little War" is the nineteenth episode of the second season of the American science-fiction television series, Star Trek, first broadcast February 2, 1968, and repeated on August 23, 1968. The screenplay was written by Gene Roddenberry, based on a story by Don Ingalls under the pseudonym Jud Crucis, and directed by Marc Daniels. It was intended as an allegory about America's involvement in the Vietnam War.

In the episode, the crew of the Enterprise discovers Klingon interference in the development of a formerly peaceful planet and joins them in what becomes an arms race.

On stardate 4211.4, the Federation starship USS Enterprise arrives at the planet Neural, 3rd planet in the Zeta Boötis System. Upon their arrival, Chief Medical Officer Dr. McCoy finds the planet is a medical treasure trove of materials needed for various serums and drugs. Captain Kirk also reports that the people of the world are still primitive.

Kirk and First Officer Spock soon notice a group of villagers crouching in the nearby rocks, apparently preparing for an ambush. Kirk is shocked to see they possess flintlock long guns and other firearms. Moreover, they seem to be waiting not for game but for a group of Hill People, one of whom Kirk recognizes as Tyree, his closest friend on this world. Since the landing party aren't supposed to use phasers, Kirk tosses a rock to make a distraction, but this causes one of the natives' guns to go off and a chase ensues. Spock is shot by one of the natives.

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