The 25 Greatest Space Aliens on the Star Trek TV Shows, Ranked

From masters of war to space hippies, the Star Trek TV universe is so jam-packed with aliens it can be hard to know where to start.

That's where we come in: We've reviewed non-Earthling species that appear in at least one of the five Star Trek series, taken into account a being's intellect, charisma and power, assessed its significance to the canon, and ranked accordingly.

Here's the rundown of Star Trek's greatest TV aliens, from the pretty cool to the very cool.

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These humanoids make their mark by going to crazy extremes. In the Season 1 Star Trek: The Next Generation episode "Justice," the Edo tout free love … and then try to execute Wesley (Wil Wheaton) for knocking over a couple of plants.

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According to the Season 2 Star Trek: The Original Series episode, "A Piece of the Action," the Iotians learn everything about civilization from a single book, Chicago Mobs of the Twenties, which is bad, but fun.  

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Not only is Balok terrifying-looking in the Season 1 Star Trek: The Original Series episode, "The Corbomite Maneuver," he also turns out to be a mere front for a more-terrifying alien (played by a tiny, bald, tippling Clint Howard).

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Star Trek: The Next Generation's Deanna Troi is the franchise's best-known member of this telepathic species, which gets points for being, yay, telepathic, but fails to rank higher for lacking a cool visual hook, like a big head.

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The tears of the feisty female members of this humanoid species turn men into love slaves as no less than Captain Kirk (William Shatner) learns in the Season 3 Star Trek: The Original Series episode, "Elaan of Troyius."  

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We love these old Star Trek hands, seen throughout the various series, for the antennae that remind of us old TV sets, and for the blue Andorian ale that reminds us of a swingin' cocktail.  

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We first meet the Tiburonians in the form of Dr. Sevrin, the charismatic scientist turned cult leader in the Season 3 Star Trek: The Original Series episode, "The Way to Eden." Any alien species who can corral space hippies is right by us.

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The typical Federation male's fetishizing of the Orion "slave girl" is, at minimum, icky. But judging by the pecs on display in the Season 4 Star Trek: Enterprise episode, "Borderland," the green-hued species is an equal-opportunity skin-peddler.  

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Most of the time, Star Trek: Deep Space Nine's Odo looks like a man whose face has been rendered motionless by too much cosmetic surgery. (Not that there's anything wrong with that.) But he, like his fellow Changelings, can literally pour himself into any shape.  

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In the Season 2 Star Trek: The Original Series episode, "Who Mourns for Adonais?", Trek puts a brilliant new twist on our old mythology: The Greek gods, including Apollo, weren't merely real. They were super-human space aliens.

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Among Star Trek's big-headed aliens, none are bigger, in a figurative sense, than the Talosians. They are the very first aliens from the very first Star Trek adventure, the unaired Star Trek: The Original Series pilot, "The Cage," which was later repurposed for the episode, "The Menagerie."

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In outer space, as on Earth, you want a bartender who's steady, experienced and a good listener. So, you pretty much want the age-defying, unflappable El-Aurians, such as Star Trek: The Next Generation's Guinan (Whoopi Goldberg).

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This species consists of organisms who live inside host bodies, and, judging by Star Trek: Deep Space Nine's Jadzia Dax (Terry Farrell), they are also fearless, capable leaders.  

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Some Xindi look like bugs, some look like reptiles, some look like fish, and on and on. Together, they're the collective menace of Star Trek: Enterprise's Season 3, and the makers of the Florida-destroying Xindi probe.

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The space station of Star Trek: Deep Space Nine literally revolves around the home planet of this war-weary species, represented in Sisko's team in the form of Kira Nerys (Nana Visitor).

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Meet the folks who are the reason the Bajorans are so war-weary: the Cardassians, the overarching foes of Star Trek: Deep Space Nine.  

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Rather than an organic alien species, these armor-faced folks, another of Star Trek: Deep Space Nine's prominent players, were designed by the Dominion collective to be combatants.  

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These elusive, all-powerful baddies from Star Trek: Voyager are so powerful that they force the Borg to make nice with Captain Janeway (Kate Mulgrew) in order to survive.

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This cool customer, a starship captain in his own right, goes toe-to-claw with Kirk in the Season 1 Star Trek: The Original Series episode, "Arena." Not only that, he beats the Sleestak to the lizard-head look by almost a decade.  

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When you think Star Trek villains, you think Romulans (almost) every time. Of all the enduring Federation foes, the war-mongering Romulans arrived on the scene first.

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They eat, they purr, they procreate, and from the time they overran the Enterprise in the Season 2 Star Trek: The Original Series episode, "The Trouble With Tribbles," their limited talents have owned our hearts.

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As we noted, the Romulans came first, but the Klingons made the loudest bang. Not only have they spanned the various TV series and movies (as have, yes, the Romulans), but they've been depicted as crossing over into Federation ranks.  

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Resistance is indeed futile. We have nothing but respect for this devastating alien form with an all-out appetite for technology.  

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Q -- being from another dimension (played by John de Lancie) -- outranks the Borg because, one, he brokered the first Enterprise-Borg meeting, and, two, he's got a heck of a lot more charm and wit.

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From the Enterprise's first TV voyage, this species has represented, and Mr. Spock (Leonard Nimoy) has captivated. Our adoration, therefore, is nothing if not logical.  

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