Live-action

• A for Andromeda (franchise):
  • A for Andromeda (1961, UK)
  • Andromeda Breakthrough, The (1962, UK, A for Andromeda sequel)
  • A for Andromeda (2006, UK, A for Andromeda remake)
• Aaron Stone (2009–2010, US/Canada)
• Adam Adamant Lives! (1966–1967, UK)
• Adventures of Brisco County, Jr., The (1993–1994)
• Adventures of Don Quick, The (1970, UK)
• Adventures of the Elektronic, The a.k.a. Priklyucheniya Elektronika (1980, Soviet Union, miniseries)
• After, The (2014, pilot)
• Agent Carter (2015-2016)
• Agents of S.H.I.E.L.D. (2013–2020)
• Airwolf (1984–1987)
• ALF (franchise):
  • Project ALF (1996, ALF sequel, film)
  • ALF (1986–1990)
• Alias (2001-2006)
• Alice (2009, miniseries)
• Alien (2024)
• Alien Hunter (2003, film)
• Alien Nation (franchise):
  • Alien Nation (1989–1990)
  • Alien Nation: Dark Horizon (1990, first film)
  • Alien Nation: Body and Soul (1995, second film)
  • Alien Nation: Millennium (1996, third film)
  • Alien Nation: The Enemy Within (1996, fourth film)
  • Alien Nation: The Udara Legacy (1997, fifth film)
• Alienated (2003–2004, Canada)
• Aliens in the Family (1987, UK)^[1][2] IMDb 
• Aliens in the Family (1996)
• Almost Human (2013–2014)
• Alpha Scorpio (1974, Australia)
• Alphas (2011–2012)
• Altered Carbon (2018)
• Amanda and the Alien (1995, UK, film)
• Amazing Stories (1985–1987, anthology)
• Amazon (1999, Canada/Germany)
• Ambassador Magma (1966–1967, 1993, Japan) a.k.a. Space Giants, The (US)
• American Gothic (1995–1996)
• Andra (1976, Australia) IMDb 
• Andro-Jäger, Der (1982–1984, Germany)
• Android Kikaider a.k.a. Jinzô ningen Kikaidâ (1972–1973, Japan)
• Andromeda (2000–2005)
• Angel (1999–2004) (elements of science fiction)
• Animorphs (1998–1999)
• Another Life (2019–2021)
• Aphrodite Inheritance, The (1979)
• Aquila (1997–1998, UK)
• The Ark (2023-present)
• Ark II (1976)
• Ascension (2014)
• Astronauts (1981, UK)
• Atom Squad (1953–1954)
• Atomic Rulers of the World (1964, film)
• Automan (1983–1984)
• Avengers, The (franchise, UK):
  • New Avengers, The (1976–1977, UK, Avengers, The sequel)
  • Avengers, The (1961–1969, UK)
• Aventuras En El Tiempo a.k.a. Adventures in Time (2001, Mexico)
• Avenue 5 (2020–2022)
• Awake (2012)
• Away (2020)

Animated

• Acrobunch (1982, Japan, animated)
• Action Man (franchise):
  • Action Man (1995, UK, animated)
  • Action Man (2000, UK, animated)
  • A.T.O.M. (Alpha Teens On Machines) (2005–2006, Action Man spin-off, France, animated)
• Adventures of the Galaxy Rangers, The (1986–1989, animated)
• Adventures of Jimmy Neutron: Boy Genius, The a.k.a. Jimmy Neutron (franchise):
  • Adventures of Jimmy Neutron: Boy Genius, The (2002–2006, animated)
  • The Egg-pire Strikes Back (2003, special, animated)
  • Operation: Jet Fusion (2003, film, animated)
  • Jimmy Timmy Power Hour, The (2004, film, animated)
  • Attack of the Twonkies (2004, film, animated)
  • League of Villains, The (2005, film, animated)
  • Jimmy Timmy Power Hour 2: When Nerds Collide, The (2006, film, animated)
  • Jimmy Timmy Power Hour 3: The Jerkinators, The (2007, film, animated)
  • Planet Sheen (2010–2012, Adventures of Jimmy Neutron: Boy Genius, The spin-off, animated)
• Æon Flux (1991–1995, animated)
• Aldnoah.Zero (2014–2015, Japan, animated)
• ALF: The Animated Series (1987–1989, ALF spin-off, animated)
• Alien News Desk (2019, animated)
• Alien Racers (2005, animated)
• Alienators: Evolution Continues (2001–2002, US, animated) a.k.a. Evolution: the Animated Series (UK)
• Amazing 3, The (1965–1966, Japan, animated)
• Amazing Screw-On Head, The (2006, pilot, animated)
• Android Announcer Maico 2010 (1998, Japan, animated)
• Angel Links (1999, Japan, animated)
• Ani*Kuri15 (2007–2008, Japan, animated short) (elements of science fiction in some episodes)
• Aquaman (1968–1970, animated)
• Aquatic Language (2002, Japan, short film, animated)
• Archie's Weird Mysteries (1999–2000, animated)
• Argai: The Prophecy a.k.a. Argaï: La prophétie (2000, France, animated)
• Argevollen (2014, Japan, animated)
• Aria (2005–2008, Japan, animated)
• Armored Police Metal Jack (1981, Japan, animated)
• Armored Trooper Votoms (1983–1984, Japan, animated)
• Arpeggio of Blue Steel (2013, Japan, animated)
• Astro Boy (franchise):
  • Astro Boy (1963–1966, Japan, animated)
  • Astro Boy (1980–1981, Japan, animated)
  • Astro Boy (2003–2004, Japan, animated)
• Astroganger (1972–1973, Japan, animated)
• Atomic Betty (2004–2008, Canada/France, animated)
• Attack of the Killer Tomatoes: The Animated Series (1990–1992, animated)
• Aura Battler Dunbine (1983–1984, Japan, animated)
• Avenger (2003, Japan, animated)
• Avengers, The (franchise):
  • Marvel's Avengers Assemble (2013–2019, animated)
  • Avengers: Earth's Mightiest Heroes, The (2010–2012, animated)
  • Avengers: United They Stand, The (1999–2000, animated)