Polyphemus is a Cyclops in Greek mythology. The name "Polyphemus" may also refer to:

• Polyphemus (Argonaut), another figure from Greek mythology
• Antheraea polyphemus, or Polyphemus moth, a giant silk moth of North America
• Polyphemus (crustacean), a genus of cladocerans
• Limulus polyphemus, the Atlantic horseshoe crab
• Mecynorhina polyphemus, a species of beetle
• Polyphemus (book), a collection of short stories by Michael Shea
• Polyphemus (Reni), a 1639–1640 painting by Guido Reni
• Polyphemus (sculpture), an 1888 bronze by Auguste Rodin
• Polifemo, an Italian opera by Nicola Porpora
• The name of the gas giant in the Avatar series, which Pandora orbits.

See also

• HMS Polyphemus, the name of several ships of the British Royal Navy
• Polyphem (missile), a cancelled surface-to-surface missile project
• Polyphemus#Possible origins, for folktales similar to that of Homer's Polyphemus