The Star Trek franchise has taken viewers to strange new worlds. Since the first series premiered in 1966, the franchise has introduced some of the best alien species in science fiction history. Star Trek has also introduced some of the most evil aliens and cruelest villains that can be seen on television.
While there are some epic villains in every series, some villains stand out above the rest. They are so memorable that they can carry viewers' nostalgia when looking back at the series. And some have found ways to return by reaching out across series, demonstrating their might.
8 The Original Series: Khan Noonien Singh
Khan only appeared in one episode of Star Trek: The Original Series, but that one appearance was compelling enough that he became the main villain of a feature film. He was a genetically-engineered superhuman who had gained control of Earth. He was overthrown and sent to space where he appeared in The Original Series episode "Space Seed."
Khan was banished again, but would return in Star Trek II: The Wrath of Khan as a cult leader who nearly takes over the Enterprise until Spock gives his life to save the crew. In this now-classic film, Khan made Star Trek popular again, leading to the future shows.
7 The Next Generation: The Borg
The Star Trek: The Next Generation crew faced several intense villains that could have landed in this spot, especially the always memorable Q. But only the Borg was able to assimilate the Captain of the Enterprise, turning him against his own people. The Borg also expanded as a threat in the film Star Trek: First Contact.
The Borg would go from planet to planet assimilating aliens into the Borg's collective hivemind. The aliens would also use up all the resources on the planet. The Borg can quickly adapt allowing them to eliminate any threat.
6 Deep Space 9: Gul Dukat
A member of the Cardassian race, Gul Dukat was the former head of the Deep Space 9 space station before the Federation took over. As the Cardassians had major issues with the Federation, it makes sense that Dukat would take issue with the Federation taking over the space station.
Dukat committed a number of atrocities while he was in charge, especially against the Bajoran people. While he would sometimes have an uneasy alliance with Captain Benjamin Sisko, his warped perceptions prevented him from truly redeeming himself. He would go on to become a religious fanatic serving a higher power who was more villainous but less memorable.
5 Voyager: The Borg Queen
While the Borg as a whole have created problems across multiple Star Trek series, the Borg Queen wreaked more havoc on Voyager than any other villain. She was a master manipulator who could pull anyone into her grasp. Her connection to the first Borg Starfleet crew member, Seven of Nine, made her a much stronger villain than most.
The Borg Queen would continue her manipulative ways in the Paramount+ era of Star Trek, with her manipulation becoming a major theme of the second season of Star Trek: Picard.
4 Enterprise: The Xindi
While Star Trek: Enterprise is often viewed as a disappointing series, the Xindi attack of the third season is considered to be its strongest story arc. The Xindi attacked Earth to try to prevent the Starfleet from attacking them. Instead, it led to Starfleet commissioning Captain Jonathan Archer and the Enterprise crew to respond.
The Xindi were a species featuring six different sentient forms who lived in the Delphic Expanse. The Xindi attack led to the formation of United Earth, who became an important member of the United Federation of Planets.
3 Discovery: Captain Gabriel Lorca
The first Captain of the starship Discovery turned out to be its greatest foe. Captain Gabriel Lorca appeared to be a capable Starfleet officer, helming one of its finest starships. But Discovery's visit to the Mirror Universe toward the end of season one reveals that he is actually a refugee from the Mirror Universe hellbent on overthrowing its Emperor.
Played to perfection by Jason Isaacs, Lorca is commanding and sincere when he needs to be and equally frightening once the tables have turned. He may have only been in one season of the show, but he remains a standout villain.
2 Picard: The Changelings
While Star Trek: Picard revisited his interactions with the Borg and the Borg Queen in season two, it was the Changelings in season three who presented the greatest threat. The Changelings were hunting down Picard's son with Beverly Crusher, Jack Crusher.
The Changelings want revenge on the Federation for what happened during the Dominion War. They worked out a plan to try to take over Starfleet from the inside.
1 Strange New Worlds: The Romulans
Strange New Worlds finds a perfect way to blend The Original Series with Discovery to introduce the Romulans to its story. Captain Pike is on a mission to prevent a tragic fate he foresaw during the events of season two of Discovery. He ends up presented with the scenario and must live out the same decision Captain Kirk did in The Original Series episode "Balance of Terror."
Pike doesn't handle the situation well and ends up starting a decades-long war with the Romulans. The showrunners came up with an excellent way to introduce the Romulans, since previous Star Trek canon would have prevented them from appearing before Kirk took command.