Top 10 Star Trek: The Original Series Episodes

When a virus infects the Enterprise, inhibitions are tossed out the nearest airlock. Under the hyper-drunk influence of the affliction, Nurse Chapel professes her love for Spock, Kirk for his ship, and Sulu for topless fencing. Oh my! Meanwhile, the restoration of the ship’s decaying orbit around Psi 2000 is complicated when control of the vessel is taken over by a surly Irishman, who’s determined to entertain the crew with an impromptu variety show.

Undoubtedly the cuddliest installment of the original series, this episode is packed with humor, wheat and bar fights. While on guard duty at K7, the Enterprise and the station are overrun by tribbles. Displaying both a natural love for chicken sandwiches and a hatred of Klingons, the fast-breeding fluff balls become heroes when they expose Arne Darvin as the clean-shaven, suit-wearing Klingon saboteur responsible for poisoning the station’s wheat. Thanks tribbles!

While trying to aid the USS Constellation, the Enterprise comes face-to-face with the hellish maw of the Doomsday Machine. With Kirk and Scotty trapped aboard the damaged ship, Commodore Decker – the Constellation’s captain and sole survivor – takes command of the Enterprise with the aim of destroying the weapon. Although Kirk saves the day, the highlight here is guest-star William Windom, who channels both Captain Ahab and Humphrey Bogart while delivering a multilayered blend of authority, vengeance, and vulnerability.

In one of the signature moments of the series, Captain Kirk goes up against a Gorn commander in hand-to-hand combat. Realizing he can’t win, he hatches a crafty plan but accidentally shares it with his rival on an open comm-channel. Amazingly, his plan is not successful, but Kirk makes up for the blunder with an act of genius by re-inventing gunpowder and making a diamond-shooting gun out of stuff that’s just lying around.

After a transporter glitch, Kirk, Scotty, McCoy, and Uhura find themselves in a parallel, pirate universe. Here, sleeves are optional, sports bras are standard issue, and everyone’s just a bit evil. Oh, and Spock has a beard. In an episode that created the Beard of Evil meme, Kirk and company must hide their true nature and avoid assassination attempts from Chekov and Sulu, while trying to get back to their own reality.

When the Enterprise team discovers the crew of an ancient Earth ship in suspended animation, it’s exciting times for historians; but things go south quick when the group’s leader, Khan Noonien Singh, is revived. What ensues is a mule-kicking and axe handle-smashing fight between Kirk and the genetically-engineered Khan (and their respective stunt doubles) for control of the ship. When the Captain exiles Khan to Ceti Alpha V, the seeds for the film “Star Trek II: The Wrath of Khan” are planted.

The Enterprise is en-route to a diplomatic conference on Babel when the Tellarite delegate is killed. Suspicion falls on the Vulcan ambassador, Spock’s ailing father Sarek; but that theory is proven wrong when Thelev attacks Kirk and is revealed as an imposter. Assumed by Spock to be a cosmetically altered Orion, the assassin would rather commit suicide than talk. The episode is notable for introducing the Andorians, Tellarites, and the troubled relationship between Spock and his father.

Suffering the effects of pon farr, Spock returns to Vulcan to get lucky with his long betrothed bride, T’Pring. However, the would-be Mrs. Spock instead challenges our favorite pointy-eared hobgoblin to a death-match against Captain Kirk. A pop-culture goldmine, this is the episode that introduced the famous Vulcan salute, Spock’s catchphrase, Ensign Chekov, and the signature fight music that has since become a parody staple.

When several Federation outposts are destroyed near the neutral zone, it sparks the return of a long-silent foe, the Romulans. Although the Romulan Warbird has a cloak, this episode establishes that a ship can’t fire its weapons while the device is in use. When Kirk pursues the cloaked ship, it becomes a thrilling submarine hunt in space, as well as a battle of wits and dirty tricks between him and the unnamed Romulan commander, played by Mark Lenard.

Before we unveil our top pick here are a few honorable mentions:
- “The Menagerie” (Season 1, Episodes 11-12)
- “This Side of Paradise” (Season 1, Episode 24)
- “Where No Man Has Gone Before” (Season 1, Episode 3)
- “Shore Leave” (Season 1, Episode 15)
- “The Ultimate Computer” (Season 2, Episode 24)

An overly medicated Dr. McCoy jumps through a time portal to the 1930s, causing the Nazis to win World War II and erasing the Federation from history. Need more? Kirk and Spock follow Bones, and learn he saved the life of a pacifist who will help delay America’s entry into the war. Despite falling for her, Kirk realizes Edith Keeler must die to restore time and watches in horror as she is killed by a truck.

Do you agree with our list? What’s your favorite Star Trek episode? For more fascinating Top 10s published daily, be sure to subscribe to WatchMojo.com.