Hugo Award for Best Series
The Hugo Award for Best Series is one of the Hugo Awards given each year for science fiction or fantasy stories published or translated into English during the previous calendar year. The award is available for series of science fiction or fantasy stories published consisting of at least 3 works totaling at least 240,000 words, with at least one work released or translated into English during the previous calendar year. A losing finalist becomes eligible again with the publication of at least two new works totaling at least 240,000 words. The Hugo Award for Best Series has been awarded annually since 2017. It was started then as a one-time special Hugo Award in advance of a vote to make it a permanent category, and was ratified as such by members of the World Science Fiction Society that year.
In addition to the regular Hugo awards, beginning in 1996 Retrospective Hugo Awards, or "Retro Hugos", have been available to be awarded for 50, 75, or 100 years prior. Retro Hugos may only be awarded for years after 1939 in which no awards were originally given. To date, Retro Hugo awards have been given for series for 1945.
Hugo Award nominees and winners are chosen by supporting or attending members of the annual World Science Fiction Convention, or Worldcon, and the presentation evening constitutes its central event. The selection process is defined in the World Science Fiction Society Constitution as instant-runoff voting with six nominees. The series on the ballot are the six most-nominated by members that year, with no limit on the number of series that can be nominated. Initial nominations of five works each are made by members in January through March, while voting on the ballot of six nominations is performed roughly in April through July, subject to change depending on when that year's Worldcon is held. Worldcons are generally held near the start of September, and are held in a different city around the world each year.
In the 5 nomination years, 27 series by 27 authors have been nominated, including co-authors and Retro Hugos. The first year was won by Lois McMaster Bujold's Vorkosigan Saga, begun in 1986 and consisting of over 20 novels and short stories. Bujold also won the second year for her World of the Five Gods series, begun in 2000 and consisting of 3 books and 6 novellas, while Becky Chambers won for her Wayfarers series of 3 novels. Bujold, Seanan McGuire, and James S. A. Corey are the only authors with multiple nominations, with McGuire nominated twice for The October Daye Books and twice for the InCryptid series, and Corey twice for The Expanse series. McGuire and Corey are the only authors to be nominated twice for the same series.
Winners and nominees
In the following table, the years correspond to the date of the ceremony, rather than when the story was first published. Entries with a blue background have won the award; those with a white background are the other nominated works.* Winners and joint winners
| Year | Author | Series | Publisher | Ref. |
| 2017 | * | Baen Books | ||
| 2017 | Tor Books | |||
| 2017 | Orbit Books | |||
| 2017 | DAW Books / Corsair Books | |||
| 2017 | Victor Gollancz Ltd / Del Rey Books / DAW Books / Subterranean Press | |||
| 2017 | Del Rey Books / Harper Voyager UK | |||
| 2018 | * | World of the Five Gods | Harper Voyager / Spectrum Literary Agency | |
| 2018 | Night Shade Books | |||
| 2018 | Broadway Books | |||
| 2018 | InCryptid | DAW Books | ||
| 2018 | Tor Books / Titan Books | |||
| 2018 | Tor Books / Victor Gollancz Ltd | |||
| 2019 | * | Wayfarers | Hodder & Stoughton / Harper Voyager | |
| 2019 | Tor.com Publishing | |||
| 2019 | Tor.com Publishing / Orbit Books | |||
| 2019 | Machineries of Empire | Solaris Books | ||
| 2019 | DAW Books | |||
| 2019 | Subterranean Press | |||
| 2020 | Orbit Books | |||
| 2020 | InCryptid | DAW Books | ||
| 2020 | Luna | Tor Books / Victor Gollancz Ltd | ||
| 2020 | Planetfall series | Ace Books / Victor Gollancz Ltd | ||
| 2020 | Winternight Trilogy | Del Rey Books | ||
| 2020 | Orbit Books |
Retro Hugos
Beginning with the 1996 Worldcon, the World Science Fiction Society created the concept of "Retro Hugos", in which the Hugo award could be retroactively awarded for years 50, 75, or 100 years before the current year, if no awards were originally given that year. Retro Hugos have been awarded seven times, for 1939, 1941, 1943—1946, 1951, and 1954, though only once for series. Retro Hugos for series do not note the original publishers.| Year | Year awarded | Author | Short story | Ref. |
| 1945 | 2020 | Captain Future | ||
| 1945 | 2020 | |||
| 1945 | 2020 | et. al. | ||
| 1945 | 2020 | Doc Savage | ||
| 1945 | 2020 | Doc Savage | ||
| 1945 | 2020 | Jules de Grandin | ||
| 1945 | 2020 | Pellucidar | ||
| 1945 | 2020 | The Shadow |