The following list is the Official Definitive List of the 250 best movies about aliens and/or alien invasions of all time.
I averaged 13 different ranked lists of “Best alien movies of all time” to get this definitive compilation.  See my Methodology page for the research process that was used, including all 13 lists that were averaged.

  1. The Thing (1982)
  2. Close Encounters of the Third Kind (1977)
  3. Alien (1979)
  4. E.T. the Extra-Terrestrial (1982)
  5. Aliens (1986)
  6. Predator (1987)
  7. District 9 (2009)
  8. Arrival (2016)
  9. Independence Day (1996)
  10. Star Wars: Episode V – The Empire Strikes Back (1980)
  11. Invasion of the Body Snatchers (1978)
  12. The Day the Earth Stood Still (1951)
  13. Signs (2002)
  14. They Live (1988)
  15. Edge of Tomorrow (2014)
  16. Under the Skin (2013)
  17. Invasion of the Body Snatchers (1956)
  18. Star Wars: Episode IV – A New Hope (1977)
  19. Men in Black (1997)
  20. The Avengers (2012)
  21. War of the Worlds (2005)
  22. Annihilation (2018)
  23. Mars Attacks! (1996)
  24. The Fifth Element (1997)
  25. Starship Troopers (1997)
  26. Attack the Block (2011)
  27. Guardians of the Galaxy (2014)
  28. Contact (1997)
  29. Avengers: Endgame (2019)
  30. The Abyss (1989)
  31. Avengers: Infinity War (2018)
  32. The World’s End (2013)
  33. The War of the Worlds (1953)
  34. The Faculty (1998)
  35. Fantastic Planet (1973)
  36. Quatermass and the Pit (1967)
  37. A Quiet Place (2018)
  38. Galaxy Quest (1999)
  39. Star Trek II: The Wrath of Khan (1982)
  40. Star Trek (2009)
  41. Cloverfield (2008)
  42. Super 8 (2011)
  43. Night of the Creeps (1986)
  44. Avatar (2009)
  45. 10 Cloverfield Lane (2016)
  46. Starman (1984)
  47. Color Out of Space (2019)
  48. Slither (2006)
  49. Prometheus (2012)
  50. Pitch Black (2000)
  51. Invaders from Mars (1953)
  52. Solyaris (1972)
  53. The Man Who Fell to Earth (1976)
  54. 2001: A Space Odyssey (1968)
  55. Thor: Ragnarok (2017)
  56. Interstella 5555: The 5tory of the 5ecret 5tar 5ystem (2003)
  57. Star Trek: First Contact (1996)
  58. Paul (2011)
  59. Pacific Rim (2013)
  60. The Hidden (1987)
  61. Star Wars: Episode VI – Return of the Jedi (1983)
  62. The Thing from Another World (1951)
  63. Lifeforce (1985)
  64. Monsters (2010)
  65. Lilo & Stitch (2002)
  66. Life (2017)
  67. Village of the Damned (1960)
  68. Critters (1986)
  69. Star Trek Into Darkness (2013)
  70. The Fourth Kind (2009)
  71. Plan 9 from Outer Space (1957)
  72. Alien vs. Predator (2004)
  73. Man Facing Southeast (1986)
  74. Midnight Special (2016)
  75. Total Recall (1990)
  76. Dark Skies (2013)
  77. Star Trek IV: The Voyage Home (1986)
  78. Stargate (1994)
  79. Oblivion (2013)
  80. Guardians of the Galaxy Vol. 2 (2017)
  81. Evolution (2001)
  82. Alien: Covenant (2017)
  83. The X Files (1998)
  84. Superman (1978)
  85. Quatermass 2 (1957)
  86. Captain Marvel (2019)
  87. Transformers (2007)
  88. The Blob (1988)
  89. Ender’s Game (2013)
  90. The Arrival (1996)
  91. Men in Black 3 (2012)
  92. Macross: Do You Remember Love? (1984)
  93. Repo Man (1984)
  94. Spaceballs (1987)
  95. The Brother from Another Planet (1984)
  96. Battle Los Angeles (2011)
  97. It Came from Outer Space (1953)
  98. The Mysterians (1957)
  99. Venom (2018)
  100. I Married a Monster from Outer Space (1958)
  101. Predators (2010)
  102. Space Jam (1996)
  103. Star Trek Beyond (2016)
  104. Alien 3 (1992)
  105. Fire in the Sky (1993)
  106. Men in Black II (2002)
  107. Alien: Resurrection (1997)
  108. Forbidden Planet (1956)
  109. Kronos (1957)
  110. Star Wars: Episode VII – The Force Awakens (2015)
  111. Earth vs. the Flying Saucers (1956)
  112. Predator 2 (1990)
  113. It (2017)
  114. The Thing (2011)
  115. Muppets from Space (1999)
  116. Destroy All Monsters (1968)
  117. Event Horizon (1997)
  118. V (1983)
  119. Interstellar (2014)
  120. Star Wars: Episode VIII – The Last Jedi (2017)
  121. Superman II (1980)
  122. Star Trek VI: The Undiscovered Country (1991)
  123. Treasure Planet (2002)
  124. Bad Taste (1987)
  125. Save the Green Planet! (2003)
  126. Dark City (1998)
  127. Voyage to the End of the Universe (1963)
  128. Altered (2006)
  129. Man of Steel (2013)
  130. Rogue One: A Star Wars Story (2016)
  131. Sphere (1998)
  132. It Chapter Two (2019)
  133. Invasion of Astro-Monster (1965)
  134. The Rocky Horror Picture Show (1975)
  135. Cowboys & Aliens (2011)
  136. The Chronicles of Riddick (2004)
  137. Dreamcatcher (2003)
  138. From Beyond (1986)
  139. Body Snatchers (1993)
  140. Captive State (2019)
  141. Dune (1984)
  142. Time Masters (1982)
  143. The Mist (2007)
  144. Enemy Mine (1985)
  145. Gandahar (1987)
  146. Bumblebee (2018)
  147. Communion (1989)
  148. Monsters vs. Aliens (2009)
  149. Killer Klowns from Outer Space (1988)
  150. Taken (2002)
  151. The Vast of Night (2019)
  152. The Predator (2018)
  153. V: The Final Battle (1984)
  154. The Last Starfighter (1984)
  155. This Island Earth (1955)
  156. Thor (2011)
  157. Invaders from Mars (1986)
  158. Dark Angel (I Come in Peace) (1990)
  159. Species (1995)
  160. Invasion of the Triffids (1963)
  161. Daleks’ Invasion Earth: 2150 A.D. (1966)
  162. The Avengers: Age of Ultron (2015)
  163. Ultimate Avengers: The Movie (2006)
  164. The Andromeda Strain (1971)
  165. The Puppet Masters (1994)
  166. Village of the Damned (1995)
  167. The Watch (2012)
  168. Critters 2: The Main Course (1988)
  169. Transformers: Revenge of the Fallen (2009)
  170. The Blob (1958)
  171. Godzilla 2000 (1999)
  172. Justice League: War (2014)
  173. Impostor (2001)
  174. Not of This Earth (1957)
  175. Strange Invaders (1983)
  176. Cocoon (1985)
  177. Final Fantasy: The Spirits Within (2001)
  178. Xtro (1982)
  179. V/H/S/2 (2013)
  180. The Andromeda Strain (2008)
  181. The Deadly Spawn (1983)
  182. Deadpool 2 (2018)
  183. Transformers: Dark of the Moon (2011)
  184. Solaris (1972)
  185. The Invasion (2007)
  186. The Hitchhiker’s Guide to the Galaxy (2005)
  187. Grabbers (2012)
  188. Mission to Mars (2000)
  189. Invasion of the Saucer Men (1957)
  190. Returner (2002)
  191. Star Wars: Episode III – Revenge of the Sith (2005)
  192. Contamination (1980)
  193. Them! (1954)
  194. Power Rangers (2017)
  195. Chicken Little (2005)
  196. Thor: The Dark World (2013)
  197. Red Planet (2000)
  198. Spaced Invaders (1990)
  199. The Man from Planet X (1951)
  200. Mars Attacks the World (1938)
  201. Flight of the Navigator (1986)
  202. John Carter (2012)
  203. Killers from Space (1954)
  204. The Day the Earth Stood Still (2008)
  205. The X from Outer Space (1967)
  206. Krull (1983)
  207. Knowing (2009)
  208. Star Trek III: The Search for Spock (1984)
  209. Valerian and the City of a Thousand Planets (2017)
  210. I Am Number Four (2011)
  211. The Whisperer in Darkness (2011)
  212. Dune (2000)
  213. Zathura: A Space Adventure (2005)
  214. Ghosts of Mars (2001)
  215. Justice League (2017)
  216. Futurama: Bender’s Big Score (2007)
  217. Pandorum (2009)
  218. Fantastic Four: Rise of the Silver Surfer (2007)
  219. Escape to Witch Mountain (1995)
  220. Star Wars: Episode I – The Phantom Menace (1999)
  221. Star Trek: The Motion Picture (1979)
  222. Race to Witch Mountain (2009)
  223. Titan A.E. (2000)
  224. 2010 (1984)
  225. Alien Nation (1988)
  226. Escape to Witch Mountain (1975)
  227. Outlander (2008)
  228. The 5th Wave (2016)
  229. Coneheads (1993)
  230. Star Wars: Episode II – Attack of the Clones (2002)
  231. Star Trek: Generations (1994)
  232. Aliens vs. Predator: Requiem (2007)
  233. Species II (1998)
  234. Barbarella (1968)
  235. Explorers (1985)
  236. Lost in Space (1998)
  237. Apollo 18 (2011)
  238. The Day of the Triffids (2009)
  239. Star Trek V: The Final Frontier (1989)
  240. Screamers (1995)
  241. The Darkest Hour (2011)
  242. Star Trek: Nemesis (2002)
  243. Planet 51 (2009)
  244. Indiana Jones and the Kingdom of the Crystal Skull (2008)
  245. 20 Million Miles to Earth (1957)
  246. The Cat from Outer Space (1978)
  247. K-PAX (2001)
  248. Doom (2005)
  249. Green Lantern (2011)
  250. Starship Troopers: Invasion (2012)