The 21 Best Star Trek Original Series Episodes, Ranked

Although humorous moments abound throughout the original "Star Trek," there aren't many outright comedy episodes. In fact, there are only three: "I Mudd," "A Piece of the Action," and "The Trouble with Tribbles." Most fans I know vote the straight "Tribbles" ticket, but that episode is merely cute-funny, whereas the over-the-top "A Piece of the Action," is actually genuinely funny. The script by Gene L. Coon is more absurd than "Tribbles" and features more comic business. The cherry on top was its helmer, James Komac, who was a gifted comedy writer and director of hundreds of episodes of shows including "Welcome Back, Kotter" and "Chico and the Man" (which he created).

This episode is almost a meta-commentary and spoof on the "Star Trek" schtick of "strange new worlds" which end up being monocultures thinly based on Earth's history. Here we see why the Prime Directive exists: an entire civilization has modeled itself on the popular mythos of Roaring '20s Chicago mobs. It's literally Planet Cosplay, and an unintentional spoof of fandoms then and now. Two things keep it at this end of the list: it's shamelessly riffing on "Robin and the 7 Hoods" (1964), and it's almost irredeemably dumb. Fortunately, it's dumb fun, and fun enough to be among the best. "Right?" "Riiiiight."

This least "Star Trek"-y of "Treks" scores points for being just that. The series premise allows it to be a semi-anthology, able to shift genres without breaking format, so one week it's a psychological drama about the duality of human nature, another time it's about cold war proxies, or planet-killing doomsday machines by way of "Moby Dick," or — as in this case — a Shakespearean tragedy about mercy and revenge. Just As Hamlet must determine whether or not his uncle Claudius murdered his father, so must Captain Kirk determine if actor Anton Karidian is the man once known as Kodos the Executioner. 

Writer Barry Trivers cleverly frames his story within the play that informs it, a bit of dramaturgical license that permits a more theatrical approach. Take, for example, this bit of dialogue from Lenore Karidian: "There's a stain of cruelty on your shining armor, Captain. You could have spared him, and me. You talked of using tools. I was a tool, wasn't l? A tool to use against my father."

This episode exemplifies a shadowy aspect of Kirk's affairs rarely discussed in how he weaponizes romance to get what he wants. The ultimate irony is that he plays Karidian's daughter Lenore in order to get close to her father only to learn that she's been playing him. That it's so different is a double-edged blade that simultaneously makes it a best episode, but nowhere near the top. It was a great stretch for the show.

The third season has no classic episodes, but a few come close. "Day of the Dove" is the best of the bunch. The simple premise of exploiting bigotry between our heroes and their cold-war counterparts, the Klingons, works better than it ought. If you want to look for a message, the alien entity that fuels the very hatred and violence it feeds upon can be read as a stand-in for the military-industrial complex, which fans the flames of conflict in order to sell weapons in a perpetual feedback loop. Alternatively, you can just take it for a MacGuffin.

The nefarious influence of the alien entity memorably amplifies the slightest biases of the Enterprise crew, and it's uncomfortable to hear blatant racism coming of out our noble heroes' mouths, especially Scotty's attack on Spock. Michael Ansara plays Kang as no mere mustache-twirling bad guy, but as a shrewd enemy starship commander, an honorable warrior, and a fine opposite to Kirk. By turns personable, calculating, and violent, he's a model Original Series Klingon. Frankly, I'd rather watch him than Khan; your mileage may vary. It's got action. It's got character conflict for days. It's the best the third season has to offer, but it's not as great as the first and second-season entries coming up. 

A fan favorite for good reason, the episode depicts the loneliness of command as Kirk tries to seek and destroy a marauding alien vessel without triggering an outright war. Seeing some of the "lower decks" types makes the Enterprise feel more real and lived in and sells that Kirk's every decision has repercussions beyond the bridge. But it's Mark Lenard's perfectly pitched turn as the unnamed Romulan commander that's most memorable here. Torn over the ramifications of the performance of his duty, he's Kirk's equal in every way, and you can believe that he loses this battle not by dint of any personal failings but merely because his ship is outmatched by the much quicker and faster-firing Enterprise.

For 1966 the effects are great and largely still hold up. The Romulan ship is simple and distinctive, and the music is spot on. The main thing keeping it out of the top 10 is that it so baldly swipes elements of the films "Run Silent Run Deep" and "The Enemy Below," slapping pointed ears on the German Kriegsmarine story from the latter film, borrowing its war-weary commander and a subordinate fanatically loyal to their political leader. In "Arena," the show paid for the rights of the story it was cribbed from and credited the author. No such screen credit graces this obvious lift.

Forget "The Menagerie" with its paper-thin envelope around the first pilot, repetitive courtroom scenes, and forced cliffhangers, all of which render it a solid but not great installment. But on its own "The Cage" is not just a great launchpad for what "Star Trek" is and would become, but an imaginative and well-executed story in its own right. Gene Roddenberry's script is smart, with the atrophied Talosian aliens a satirical stand-in for TV audiences who might rather live other people's fantasies than experience adventures of their own. While it's a bit talky and static in places, when they're in action it's great stuff — notably the laser cannon scene and Pike's illusory fight on Rigel VII.

Visually it's terrific. This was the most expensive episode ever made, and it shows. The sets, costumes, makeups, and many special effects are top-notch for a show of the era particularly the matte shot of the Rigel VII fortress. The pacing's a bit loose, the characters don't pop due to the largely meh casting, and "THE WOMEN!" Number One and Yeoman Colt secretly wanting to bone the Captain is cringeworthy. However, guest star Susan Oliver's performance is the standout here, followed by Leonard Nimoy as Spock. Ultimately, it's just as well that the far more energetic William Shatner stepped in to replace Jeffrey Hunter's less-than-charismatic version of Captain Pike.

This might be a surprise but despite the second pilot weirdness of different uniforms, series crew regulars appearing not at all (McCoy, Uhura) or in different jobs (Sulu is an astrophysicist), and Spock's not-quite-there characterization and more severe makeup, the core "Star Trek"-ness is there in spades. Kirk makes a risky decision in the first act and must deal with the building consequences for the balance of the show, finally shouldering personal responsibility for his decision in the worst way possible: in order to save his ship and crew, he's forced to kill a subordinate shipmate and friend.

The episode looks great (being far more expensive than any regular production episode), repurposes the planet set built for the even more expensive first pilot, and features more optical effects than would be the norm for a production episode. Most importantly, William Shatner's Kirk projects leading-man charisma of the sort that's arguably what sold the show. It also delivers on Gene Roddenberry's original high-concept pitch of a "Wagon Train to the stars" where stories would focus on strong guest stars interacting with the recurring cast. The script is not without its flaws, and had Gary Mitchell been a tad more likable the drama would have played even better. Still, two thumbs way up.

Effectively the "third pilot" of "Star Trek," this was the first regular production episode to go before the cameras and it had the luxury of a rehearsal day, a solid director, and a fine script. It even ends with a quintessential "Trek" twist: our implacable foe ends up being an erstwhile friend. By rights, this should've been the first episode to air as it sets up the whole show, but it was nowhere near ready at the premiere, in part due to the sheer number of optical effects in post-production. Dr. McCoy is wonderful from his first appearance, and his camaraderie and professional conflict with Kirk set the stage for their entire relationship.

The weird flagship Fesarius is pure alien goodness, and the Balok puppet is iconic. Memorable business includes Sulu's countdown, Spock's logic and resulting lack of imagination, Scotty's comment about Spock's parents, and McCoy and Kirk's conflict over Bailey. A highlight is the briefing room scene, with its lived-in atmosphere with piles of tapes and empty cups of coffee showing instead of telling us how hard the crew has been working on their predicament. Likewise, the Enterprise feels like a real lived-in ship, with corridors bustling with the crew, something the show would lose as fixed costs increased and studio budgets didn't grow to match. It's one of the 10 best, held back only because it drags in some spots.

The fourth episode aired, "The Naked Time" is the foundational character-building segment of the series, peeling away the surface of Kirk and Spock and revealing a bit of what makes them tick. It's also entertaining as hell, with a slow burn as the crew is at first blissfully ignorant of the inhibition-inhibiting compound brought aboard and then having to deal with the resulting chaos. Sulu's descent into madness is charming, and George Takei was always at his most charismatic when he got to play unhinged. Sadly, neither Uhura nor Rand's secret selves get explored, and poor Chapel's reduced to pining for Spock as her primary character trait for most of the series.

The only weak spot here is that the "science" part of science fiction went out of the airlock. A collapsing planet is as preposterous an idea as the notion that the Enterprise is forced to constantly alter its orbit to study it. But guest crewman Kevin Riley is fun and Scotty gets two great lines here, the first being "I can't change the laws of physics," and the second an example of technobabble that's simple and audience-friendly: "You can't mix matter and antimatter cold!"

This world-building episode fires on all cylinders and never misses a beat. If writers then or now needed a model for how to write "Star Trek," this is it, and it's hands down the best episode penned by Dorothy "D.C." Fontana. There's a story conflict as the Enterprise ferries quarrelsome ambassadors and their aides to the titular "Babel" conference over a matter of Federation business. There's an interpersonal conflict between not just Spock and his parents but also between Spock and Kirk and Bones over relinquishing command. 

There's physical conflict as ambassadors brawl, one is murdered, and Kirk is ambushed and wounded. We meet lots of aliens, see a bit of galactic politics, and get a nail-biter of a finish as McCoy tries to perform delicate surgery while Kirk struggles to keep it together amidst attacks by a seemingly unstoppable, unknown ship.

Mark Lenard returns not as a Romulan but as Spock's Vulcan father, Ambassador Sarek, who picks up on Leonard Nimoy's Vulcan portrayal and crafts one uniquely his own. Memorable too is Reggie Nalder, whose burn-scarred face and Austrian accent accentuate his alienness in the role of the blue-skinned Andorian delegate Thelev, and established Andorians as Federation members, who would not be explored on TV for decades. Spock's family drama is a bit conventional for an alien culture, and just a dash more of the Vulcan alienness we got in Ted Sturgeon's "Amok Time" would have made this perfect.

This is the poster child for episodes that manage to become classics despite the premise being as dumb as a box of rocks. Absolutely nothing about the scenario makes a lick of sense. There's a parallel universe where all the same people end up on the same ship despite having vastly different histories and a culture of assassination. The starships in both universes happen to be on the same planet and beaming the same four people at the exact same time, and our parallel-universe leaping characters and their barbaric counterparts somehow switch wardrobes — and presumably underwear — mid-transporter beam.

What saves it is the sheer entertainment value of this gaudier imperial Starfleet and the skewed versions of familiar regulars inhabiting it. Evil Sulu's a sweaty seducer, mirror Chekov is a back-stabbing opportunist, and bearded Spock was a meme before we knew we had memes. The best Uhura performance can be found here, and Nichelle Nichols should be remembered for this over that overrated and involuntary interracial kiss. The only thing that could have made it better was had Yeoman Rand been brought back as "the Captain's Woman." The big speech to mirror Spock about the illogic of waste is Kirk at his Kirkiest, and that's the perfect capper on a perfectly entertaining classic that ranks right near the top.

No surprise here, as it tops a great many lists, but "City" excels not only because the core drama is compelling but because of the care with which it was put together. The most expensive regular production episode of the series, all the money is up there on the screen, from the period costumes to the backlot shooting, new sets, stock footage, and the flashing Guardian time donut. William Shatner, Leonard Nimoy, and DeForest Kelley are all in fine form here. Guest star Joan Collins isn't great but she's fine.

Story-wise, the fish-out-of-water situation, the incredibly high stakes, and the crushing inevitable tragedy make this the exemplary segment. Even gutted by ham-fisted staff rewrites by the "Trek" staff (in my opinion), Harlan Ellison's core story premise remains moving in spite of the on-the-nose sermon by Edith, the racist joke at Spock's expense, and the complete absence of the tragic Trooper character on whom the irony of who amongst us "matters" hinged. Kirk's episode-closing "Let's get the hell out of here" was not any kind of TV first, but it was the perfect minimalist button that the story needed. What more was there to say?