The 15 Most Controversial Star Trek Episodes Of All Time

Ever since its debut in the 1960s, the "Star Trek" franchise has been a beacon of social progressivism and inclusivity as its characters boldly forge ahead into the future. However, not all of its commentary and leaps forward have been met without controversy or widespread derision. For as groundbreaking as "Star Trek" is, not all of its stories have securely stuck the landing, stumbling in its handling of certain issues across its extensive history. Across the growing number of television series in the franchise, "Star Trek" has run into its fair share of controversy over the years, both with its fans and behind-the-scenes figures.

To be clear, what makes for a controversial episode isn't necessarily the episode's overall quality but the content within the episode itself. Several "Star Trek" episodes have quietly been omitted from their initial broadcasts or are noticeably edited in certain regions because of perceived sensitivities at the time. Other episodes have left fans debating for decades over the decisions made by the characters and how they thematically fit in the overarching franchise. Here are the 15 most controversial "Star Trek" episodes of all time.

One of the major recurring tropes in "Star Trek" involves characters visiting alien civilizations replicating a specific period and culture in Earth history. The "Star Trek: The Original Series" episode "Patterns of Force" takes this in a sinister direction, with the Enterprise visiting a planet modeled after Nazi Germany. To make matters worse, this society is in the midst of trying to exterminate inhabitants of a neighboring planet as part of its fascist agenda. Captain Kirk (William Shatner) and Spock (Leonard Nimoy) discover this culture is inspired by Starfleet historian John Gill (David Brian), who felt Nazism offered the most efficient government structure.

With its prevalent Nazi imagery, including the sight of Kirk and Spock wearing Nazi uniforms and clear Holocaust parallels, "Patterns of Force" is a thoroughly uncomfortable episode. That this episode's premise was driven by one character's assertion that the perceived efficiency of Nazism outweighed its obvious dangers makes it more awkward. The episode was banned in Germany for decades due to the country's sensitivities surrounding Nazi imagery. "Patterns of Force" didn't receive an official German dub until 1995, though its broadcast was withheld from German public television until 2011.

The third season of "The Original Series" was a mixed bag of quality, as the production endured budget cuts and creative changes behind-the-scenes. Though the episode "Plato's Stepchildren" unfortunately descends into the third season's mediocrity, it does include one moment noteworthy in television history. Forced to perform for a group of telekinetic aliens, Kirk kisses Enterprise chief communications officer Nyota Uhura (Nichelle Nichols) on the lips. The scene marked the first scripted kiss between white and Black actors in American television history.

Wary of its reception in more racially insensitive parts of the United States, the executive producers partially obscured the kiss by filming it at an odd angle. Additionally, the executives planned to film the kiss off-screen entirely, but Shatner and Nichols worked to make the filmed kiss as the take used for the actual episode. For completely different reasons, the United Kingdom banned the episode from being broadcast on the BBC for 30 years. Uncomfortable with the scenes of sadism towards the Enterprise crew, the BBC deemed "Plato's Stepchildren" too disturbing for younger audiences and kept it off the air.

"Plato's Stepchildren," unfortunately, wasn't the only episode from "The Original Series" singled out by British television censors. The third season episode "Whom Gods Destroy" features the Enterprise visiting a remote mental asylum for the criminally insane with medical treatment for its patients. Kirk and Spock discover that the cunning shapeshifter Garth (Steve Ihnat) has taken over the facility with his fellow patients. Taking Kirk and Spock prisoner, Garth plots to escape the planet with his Orion accomplice Marta (Yvonne Craig).

Frustrated over his inability to board the Enterprise, even after assuming Kirk's physical form, Garth has the real Kirk tortured. Just like the coercive use of telekinesis in "Plato's Stepchildren," the BBC was concerned about this plot point. The BBC also felt that the scantily clad Marta and her sensual dancing was inappropriate for younger viewers, banning "Whom Gods Destroy" in the United Kingdom until the '90s. German television similarly didn't air the episode until 1988 for presumably similar reasons. Simply put, Yvonne Craig was too much for British and German television to handle.

As far as endings go, "The Original Series" finale went out on a misogynistic whimper as the groundbreaking show came to a close in 1969. The series finale "Turnabout Intruder" has a vengeful ex-girlfriend of Kirk's, Janice Lester (Sandra Smith), use an alien device to switch bodies with him. Blaming widespread sexism in stifling her career progress, Lester plans to use Kirk's body to gain the professional recognition she believes she deserves. As the Enterprise crew suspect something is wrong with their captain, Lester quickly descends into hysteria and threatens to condemn any mutineers to death.

Criticism of the episode's overall quality aside, "Turnabout Intruder" suggested systemic sexism continued to plague humanity well into the enlightened 23rd century. This is made worse by Lester's characterization implying career-minded women are dangerous and shrill, with Shatner's performance as the body-swapped Lester veering into unintentional comedy. Widely reviled by the fans for its tone-deaf messaging, "Turnabout Intruder" was an embarrassing way for "TOS" to end its run.

Unfortunately, even by the '80s, culturally insensitive racial stereotypes were still prevalent on television, even in progressive shows like "Star Trek: The Next Generation." The first season episode "Code of Honor" has the Enterprise visit a planet reminiscent of a '40s caricature of Sub-Saharan Africa. Impressed by the strength of security chief Tasha Yar (Denise Crosby), the planet's leaders kidnap her with the intention to force her into marriage. As Captain Picard (Patrick Stewart) tries to rescue Yar, she is forced into a fight to the death for her freedom.

A dud upon arrival, "TNG" cast members have distanced themselves from "Code of Honor" since its airing, with Jonathan Frakes wishing it was removed from streaming services. When series creator Gene Roddenberry learned how the episode was proceeding, he reportedly had its assigned director, Russ Mayberry, fired. A notorious low point for the series, "Code of Honor" is widely regarded as one of the show's worst episodes.

For the most part, "Star Trek" keeps its action relatively family-friendly, generally avoiding overtly gory and graphic moments of violence. One major exception to this rule is the "Next Generation" first season episode "Conspiracy," with worm-like aliens possessing host bodies within Starfleet Command. Picard and Commander Riker (Jonathan Frakes) uncover the infiltration, confronting the parasites' leader possessing Lieutenant Commander Dexter Remmick (Robert Schenkkan). This leads Picard and Riker to blast Remmick apart with their phasers before killing the exposed parasite, stopping the invasion before it can begin.

When most enemies are hit by phasers, they simply glow until disintegrating in a brilliant flash of light. Not so for Remmick, whose chest graphically is blown open while his head explodes, unveiling the alien parasite controlling him from within. The oddly gory moment couldn't get past British censors, who edited the most gruesome shots out, while "Conspiracy" carried a content warning in its initial Canadian broadcast. "Conspiracy" is the most "TNG" leaned into Cronenberg levels of body horror, and on the scale, it doesn't disappoint.

"The Next Generation" certainly wasn't done dealing with cultural stereotypes in its second season, though they were played for goofier effect in the episode "Up the Long Ladder." The best way to succinctly describe this episode is that the Enterprise takes in refugees from Space Ireland. This spacefaring set of Celtic nomads maintain a bucolic lifestyle reminiscent of a pre-industrial Ireland, despite these interstellar reach. This includes a penchant for alcohol consumption and fiery-tempered women that would feel more at home in "The Quiet Man" than an episode of "TNG."

"Up the Long Ladder" has the unique distinction of something being sexist and anti-Irish all at the same time, as the Enterprise endures their passengers' antics. This is coupled with a cloning subplot that goes nowhere fast, including a moment where Riker kills a clone of himself, with no real moral dilemma involved. "Up the Long Ladder" is an episode that has to be seen to be believed, hilarious for all the wrong reasons in how it courts controversy.

"Up the Long Ladder" wasn't the only episode from "The Next Generation" to divisively reference the Irish. The third season episode "High Ground" has the Enterprise embroiled in a terrorist plot to provoke Starfleet intervention in a local conflict. This leads Picard and Data (Brent Spiner) to contemplate historical terrorist movements that succeeded in furthering political goals. Data recalls that the IRA's activities eventually led to the predicted Irish reunification in 2024.

This offhand line from Data generated a fair bit of controversy in the United Kingdom and Ireland at the time of its American broadcast. At the time, the British were still contending with an openly hostile paramilitary group vying to push them out of Northern Ireland for good. After a two-year delay, "High Ground" was broadcast on British satellite television, albeit with Data's line edited out. It wasn't until 2007 when "High Ground" was broadcast uncut on British television, though only in a late night time slot.

While "Star Trek" has presented a more tolerant vision of the future, one inclusive element it's struggled with is queer representation. After several botched attempts to bring a queer relationship to the screen, it was "Star Trek: Deep Space Nine" that presented the franchise's first same-sex kiss. The fourth season episode "Rejoined" has Jadzia Dax (Terry Farrell) meet Lenara Kahn (Susanna Thompson), the widow of one of her Trill symbiont's former hosts. The two struggle with their complicated feelings for each other, going as far as to share a passionate kiss.

After its initial airing in 1995, "Rejoined" received a significant amount of feedback from a divided fanbase over the on-screen kiss. Farrell recalls that while the majority of the phone calls received by Paramount over the episode were negative, the fan mail was largely positive. Following "Rejoined," "Star Trek" would avoid overtly queer relationships on-screen until 2016's "Star Trek Beyond" and the subsequent "Star Trek: Discovery." This marks the second time an on-screen kiss moved "Star Trek" forward, though more contentiously than it had with "Plato's Stepchildren."

The latter half of "Star Trek: Deep Space Nine" has the series become an extended war story with the devastating Dominion War. As the war for the galaxy drags on, Captain Sisko (Avery Brooks) makes increasingly morally compromising decisions to avert the Dominion from defeating the Federation. This comes to a head in the sixth season episode "In the Pale Moonlight," with Sisko working with former Cardassian spy Elim Garak (Andrew Robinson). Garak bombs a Romulan vessel and implicates the Dominion, with the Romulans declaring war on the Dominion, with Sisko tacitly agreeing to Garak's deception.

"In the Pale Moonlight" is rightfully considered one of the best episodes in "DS9," elevated by Brooks' performance as the conflicted Sisko. But just as the prolonged Dominion War story created tension behind-the-scenes, fans reflected if "DS9" had strayed too far from the franchise's idealistic roots. Similarly, fans still debate if Sisko's decisions were justifiable or counter to the Federation's principles. War leaves all participants' hands dirty, and even "Star Trek" was not without controversy in its handling of it.

Even beyond the Dominion War and "Deep Space Nine," "Star Trek" has presented its characters with major ethical challenges across the franchise's history. One episode that continues to inspire a healthy debate from the fans about the morality of a beloved character's decision is the "Star Trek: Voyager" episode "Tuvix." The second season episode has a transporter accident merge Tuvok (Tim Russ) and Neelix (Ethan Phillips) into a single composite being, Tuvix (Tom Wright). With Tuvix having a distinct personality and life of his own, Captain Janeway (Kate Mulgrew) weighs moral concerns ending his existence to restore her two lost crew members.

To be clear, "Tuvix" is generally well-regarded overall as one of the better episodes to come out of "Voyager." But just as Janeway wrestles with the moral implications of ending Tuvix's life to bring back Tuvok and Neelix, fans continue to debate over whether she made the right decision. Even the animated series "Star Trek: Lower Decks" offered its own perspective on this ethical dilemma. "Tuvix" is another example of great sci-fi writing, where the controversy isn't linked to a cultural or qualitative faux pas but a question where there is no clear right answer.

The prequel series "Star Trek: Enterprise" starts in a galaxy before the creation of the United Federation of Planets and its Prime Directive to not interfere with more primitive civilizations. The lack of this non-interference policy comes under scrutiny in the first season episode "Dear Doctor." The Enterprise encounters a dying race, with Doctor Phlox (John Billingsley) determining that their genetic potential has stagnated. Faced with this moral conundrum, Captain Jonathan Archer (Scott Bakula) decides to give them a treatment giving them more time to work with a neighboring race.

The original ending to the episode had Phlox stand against Archer's decision to intervene before the network had it rewritten to its more hopeful conclusion. Billingsley was against this change, feeling it removed the moral ambiguity central to the story and his character's arc. Fans were similarly divided by the overall episode, with its revised ending providing a cop-out for the Enterprise crew from leaving a race to presumably die. "Enterprise" featured other ethical challenge episodes, though they were generally handled more gracefully than "Dear Doctor."

When "Enterprise" ended in 2005, it concluded the franchise's renewed run on television that began in 1987 with "The Next Generation." The "Enterprise" series finale, "These Are the Voyages...," wrapped with a callback to the "TNG" era," with Riker revisiting the final adventure of Archer's Enterprise through an elaborate Holodeck simulation. Archer prepares to give a speech commemorating the official charter creating the Federation, but Chief Engineer Trip Tucker (Connor Trinneer) is killed on a mission. Seeing how Archer handles the death of a friend and leads the Federation gives Riker the inspiration he needs to make his own command decisions.

"Enterprise" viewers were incensed that the show's series finale essentially made the main cast side characters to Riker's story, told entirely within the Holodeck. That Trip's death was relegated to a simulated program was another major slight to fans of the show and character. Several cast members, including Scott Bakula, were also disappointed by how the show ultimately ended. Over a decade later, "These Are the Voyages..." is still reviled as one of the worst and most disrespectful "Star Trek" finales ever.

Klingons have received multiple radical redesigns over the course of "Star Trek" history, including at the start of "Star Trek: Discovery." The show's first season revolved around the Federation's war against the Klingon Empire approximately a decade before "The Original Series." The series opens with a shot of the redesigned Klingons, with purplish skin, elongated ridges, and less hair in favor of more pronounced ridges and alternatively shaped eyes and noses. While "Discovery" completely reinvigorated "Star Trek" on television for a new generation, fans were significantly less enthusiastic about the latest Klingon redesign.

The backlash to the new Klingon design was so vocal that "Discovery" quietly revised it to be slightly closer to classic Klingons in its second season. "Star Trek: Strange New Worlds" went a step further, making Klingons more visibly resemble their "TNG" era counterparts. By its second season, "Strange New Worlds" reversed the controversial Klingon change altogether, with the '80s design restored. The Klingon redesign ordeal is a prime example of the old axiom not to fix something that wasn't broken in the first place.

While "Star Trek" had occasionally skirted the line of including subject matter for more mature audiences, it had kept much of its on-screen content relatively family-friendly. As the franchise moved into the streaming era with "Discovery," "Star Trek" did move to slightly less kid-friendly storytelling. The first season episode "Choose Your Pain" contains the first ever use of the f-word in the franchise, including movies, as Ensign Sylvia Tilly (Mary Wiseman) shouts in excitement. This is immediately followed by chief engineer Paul Stamets (Anthony Rapp) repeating and emphasizing the same profanity, giving the audience two f-bombs for the price of one.

Fans were divided by the usage of such flagrant profanity in "Star Trek," with "Discovery" boldly going where no other show had gone before. Purists were uncomfortable with that level of vulgar language being openly used in "Star Trek," something they made clear in social media and message board posts. This would also trigger a formal complaint in Canada, where the episode was broadcast primetime and unedited without a content warning. After this, "Star Trek" would use the f-word sparingly, apart from several notable instances in "Star Trek: Picard."