[Update 1/15/2026]
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Following is a look at the Top 10 sci fi and fantsy shows of all-time based on how long they have been running. This is for non-anime genre entries and they are ranked by seasons and then by total episodes. Note that I am combining revival seasons for shows where it makes sense such as Doctor Who, The Twilight Zone, and The X-Files. I am including the upcoming season and estimated episode count for those shows that are confirmed to be returning for another year. Futurama has the chance to surpass Supernatural at some point in season count as it is going into its fourteenth year and seems like it will keep going.
Top 10 Longest-Running Sci Fi/Fantasy Shows
1. Doctor Who (1963-89, 2005-Present, BBC, 39 Seasons Totaling 892 Episodes)
This BBC staple is of course the longest-running sci fi show worldwide and possibly the longest-running non-soap opera series on television. But what is most impressive is that even if you break it up between its classic run and its revival, it still sets records. The original series ran for 26 seasons and 694 episodes which would still have it at the top of this list. The revival has fifteen seasons so far and 196 episodes (including specials), which would put it tied for second on the list based on the number of seasons. And Doctor Who is still going, though it is experiencing a pause at the moment. Seeing as it reboots itself every few years with a new Doctor, this show could stick around for quite a while, and no other sci fi series will be able to match its output. (Read more about the series at this link.)
2. Supernatural (2005-20, The CW, 15 Seasons Totaling 327 Episodes)
This show never counted as a breakout hit in its broadcast run, but it developed a dedicated audience early on and was always a strong performer for its network. Series creator Eric Kripke originally wanted Supernatural to wrap up after its fifth season, but the network wanted it to keep going. When Season 1 thru 6 started streaming on Netflix prior to the seventh season premiere, it became a hit for that streamer, and that is likely what propelled it into its record-breaking run. Fewer and fewer shows have twenty-plus episodes per season these days, so even if another genre entry goes past fifteen seasons, it likely will not top Supernatural‘s episode count. (Read more about the show at this link.)
3. Futurama (1999-2003, 2008-13, 2023-Present, FOX/Comedy Central/Hulu, 14 Seasons Totaling 180 Episodes Including the Upcoming 14th Season)
This animated sci fi comedy just made a big jump up the list based on the season numbering that Hulu is using. They are counting each of the direct-to-DVD releases as separate seasons which has it heading into its fourteenth year. This one may stick around for a while, so it is possible that it could challenge Supernatural based on the number of seasons, but it seems unlikely it will match that show’s episode count. (Read more about the show at this link.)
4. American Horror Story (2011-Present, FX, 13 Seasons Totaling 142 Episodes Including the upcoming 13th Season)
This season-long horror anthology series is heading into its thirteenth year, but this may be as high as it goes because even if it continues to fifteen seasons or more, it will not match the episode count of Supernatural or Futurama since it usually has only ten to thirteen episodes per season (sometimes even less). But its lengthy run has made AHS an important entry for genre television, and its impact will be felt for many years to come.
5. The Twilight Zone (1959-63, 1985-89, 2002-03, 2019-2020, CBS/UPN/CBS All Access, 11 Seasons Totaling 284 Episodes)
Since I combined a revival of Doctor Who with the original series above and will do that with other shows below, I am going to lump all of the seasons for The Twilight Zone together which brings it to eleven total and 284 episodes. The various incarnations are rarely run together, though, so if you don’t like the consolidated approach, I have extended the list to twenty below and you can reorder the Top 10 as you like. But The Twilight Zone has definitely been a resilient franchise that lends itself to reboots, and it may be one show that could eventually surpass Supernatural at the Number 2 slot. The revival at CBS All Access (now Paramount+) ended with two seasons, but don’t be surprised if the show pops up again somewhere down the road with yet another reboot. (Read more about the series at this link.)
6. The X-Files (1993-2002, 2016-18, FOX, 11 Seasons Totaling 218 Episodes)
This one counts as the longest-running non-anthology science fiction series (it was more sci fi than fantasy) in the United States, but it had to have the two revival seasons to get there. After it wrapped up its original run in 2002, The X-Files had nine seasons totaling 202 episodes, and Stargate: SG-1 would surpass it a few years later. But with the short-lived (and much-maligned) revival that started in 2016, the series got two more seasons and sixteen more episodes, enough to get it to the Number 6 slot on this list. Many people believe this show overstayed its welcome (even during its original run), but it still counts as a sci fi TV classic. (Read more about the series at this link.)
7. The Walking Dead (2010-2022, AMC, 11 Seasons Totaling 177 Episodes)
There was a time when it seemed like this show might go forever seeing as it went multiple years as the top-rated scripted show on all of television. But the Walking Dexit set in during the show’s seventh season, and viewership went on a steady decline. This one was destined to hit its endpoint eventually unless it was going to go beyond the comics, but AMC is doing that with the spin-offs instead. TWD wrapped up with its extended eleventh season which brought it to a grand total 177 eps. And while it became the favorite genre show to hate around its seventh year, it still has had an impressive run and has marked its place in sci fi TV history. (Read more about the show at this link.)
8. Smallville (2001-11, The WB/The CW, 10 Seasons Totaling 217 Episodes)
This Superman prequel series proved to be popular on its original network The WB and later on The CW even though it came before the big superhero boom. And perhaps it can be credited with sparking interest in the superhero sub-genre before Marvel, DC, and others took it to the bank. Before The Walking Dead and Supernatural surpassed this show’s ten seasons, it was neck-and-neck with Stargate: SG-1 as the longest-running genre entry in the States, but it managed to beat that one out by three episodes (SG-1 had 214 total). The ten-season run for Smallville is quite impressive, and even though the Arrow-verse has produced more total seasons across multiple shows, no one entry in that franchise has matched Smallville‘s run (The Flash came closest at nine seasons and 184 episodes).
9. Stargate SG-1 (1997-2007, Showtime/Sci Fi Channel, 10 Seasons Totaling 214 Episodes)
This series stood as the longest-running genre entry in the U.S. for several years before Smallville managed to overtake it. And even if you included the two movies in its episode count (which I did not above), it will still come up short of tying the superhero series by one ep. Regardless, Stargate: SG-1 had a very notable run, delivering intelligent science fiction throughout its ten seasons. And it currently ranks among the classics of sci fi TV. (Read more about the series at this link.)
10. Mission: Impossible (1966-73, 1988-90, CBS/ABC, 9 Seasons Totaling 206 Episodes)
This super-spy series crossed several genres and definitely brought in a fair amount of sci fi elements over its many seasons. One of the few ’60s genre entries to carry over into the ’70s, this show kept audiences on the edge of their seats for seven seasons during its original run. It also included crossover actors from other major sci fi shows such as Leonard Nimoy, Martin Landau, and Barbara Bain. It was brought back in the ’80s for a short-lived sequel series that saw Peter Graves return in the same role he made famous in the original run while leading a new group of spies. And later this one would be rebooted as a major film franchise.
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The Next Ten
To round out this list, I am including the next ten longest-running sci fi and fantasy shows in case you want to throw out any entries I have above and create your own Top 10. I should also make mention of the long-running comedy series Mystery Science Theatre 3000 which I have not included here. That one has run for fourteen seasons and 230 episodes (so far), but it is more of a movie-riffing show than a full-on sci fi series, so I did not include it on the list. But if you want to count it with the other sci fi shows, it would find itself at the Number 3 slot. It was running new episodes on Netflix, but the streamer has chosen not to do more seasons of the series. Joel Hodgson has since done another crowd-funding campaign to produce more seasons on his own platform Gizmoplex, so MST3K is not done yet.
11. The Outer Limits (1963-65, 1995-2002, ABC/Showtime/Sci Fi Channel, 9 Seasons Totaling 201 Episodes)
12. The Flash (2014-Present, The CW, 9 Seasons Totaling 184 Episodes)
13. Charmed (1998-2006, The WB, 8 Seasons Totaling 178 Episodes)
14. Vampire Diaries (2009-2017, The CW, 8 Seasons Totaling 171 Episodes)
15. Arrow (2012-20, The CW, 8 Seasons Totaling 170 Episodes)
16. Game of Thrones (2911-2019, HBO, 8 Seasons Totaling 73 Episodes)
17. Star Trek: The Next Generation (1987-94, Syndication, 7 Seasons Totaling 178 Episodes)
18. Star Trek: Deep Space Nine (1993-99, Syndication, 7 Seasons Totaling 176 Episodes)
19. Star Trek: Voyager (1995-2001, UPN, 7 Seasons Totaling 172 Episodes)
20. Buffy the Vampire Slayer (1997-2003, UPN/The WB, 7 Seasons Totaling 144 Episodes)
>Follow the current schedule of Sci Fi and Fantasy shows at This Link
Sci Fi/Fantasy TV Shows With the Most Episodes
It is also worth noting several early genre entries that tallied over one thousand total episodes, though that was across six seasons or less. Captain Video and His Video Rangers pioneered the genre on television, first arriving on the now-defunct DuMont network in 1949. That show aired daily for six years until 1955 and amassed over 1,500 episodes (nobody knows the exact number). Only a couple of dozen still survive, and only a handful are available on home video. Competing space opera series Space Patrol also ran daily and it totaled 1,110 episodes across five seasons during the first half of the ’50s. Considerably more of those survived, though not the entire run. Supernatural soap opera Dark Shadows debuted in 1966 and it had a run of 1,225 episodes across its six seasons.
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