| "Balance of Terror" | |
|---|---|
| Star Trek: The Original Series episode | |
| Episode no. | Season 1 Episode 14 |
| Directed by | Vincent McEveety |
| Written by | Paul Schneider |
| Featured music | Fred Steiner |
| Cinematography by | Jerry Finnerman |
| Production code | 009 |
| Original air date | December 15, 1966 |
| Guest appearances | |
| |
"Balance of Terror" is the fourteenth episode of the first season of the American science fiction television series Star Trek. Written by Paul Schneider and directed by Vincent McEveety, it first aired on December 15, 1966.
In the episode, the USS Enterprise battles a Romulan ship after investigating an unidentified assailant that has methodically destroyed Federation outposts bordering the Neutral Zone.
"Balance of Terror" introduces the cloaking device and the Romulans. Mark Lenard plays the Romulan commander; he later portrayed Spock's father Sarek in the majority of his later Star Trek appearances, as well as a Klingon captain in Star Trek: The Motion Picture.
The episode's events are explored within an alternate future in the Star Trek: Strange New Worlds (2022) episode "A Quality of Mercy".