List of fictional alien species: W
| Name | Source | Type |
|---|---|---|
| Wadi | Star Trek | |
| Waldahudin | Robert J. Sawyer's Starplex | |
| Wanderers | Noon Universe | |
| Wang's Carpets | Greg Egan's Diaspora | |
| Wankh | Jack Vance's Planet of Adventure series | Black frog-like humanoids |
| Warren Ampersand | Adventure Time | An alien can shape-shift, it has midnight blue in color when young and grey-blue; Jake the Dog's mechanical parent |
| The Watcher | Marvel Comics | |
| Waterseekers | Red Planet | |
| Weeping Angels | Doctor Who | Statue-like humanoid |
| Weevils | Torchwood | Humanoid |
| Whrloo | Larry Niven's Known Space | |
| Willis the Bouncer | Red Planet | |
| Winathians | DC Comics' Legion of Super-Heroes | |
| Wirrn | Doctor Who | |
| Wisps | Sonic the Hedgehog | Squid-like creatures of various shapes and colors |
| Wogneer | Star Trek | |
| Wolfweeds | Doctor Who | |
| Wookiees | Star Wars | Humanoid |
| Wraith | Stargate | The wraith looks like a human; the difference is the grey skin, the long hair of all of them, and some little holes in the face. |
| W'rkncacnter | Marathon Trilogy |