Ithaca most commonly refers to:

• Homer's Ithaca, an island featured in Homer's Odyssey
• Ithaca (island), an island in Greece, possibly Homer's Ithaca
• Ithaca, New York, a city, and home of Cornell University and Ithaca College

Ithaca, Ithaka or Ithica may also refer to:

• Ithaca, Queensland, a neighbourhood in Brisbane
  • Ithaca Division, a former local government area
  • Shire of Ithaca, a former local government area
  • Town of Ithaca, a former local government area
• Ithaca Creek, a creek in Brisbane
• Ithaca Creek State School, Bardon, Brisbane

• Ithaca (regional unit), the 2nd level administrative division
• Ithaca (polis), an ancient city

• Ithaca, Georgia, a place in Georgia
• Ithaca, Michigan
• Ithaca, Nebraska
• Ithaca (town), New York, a town in Tompkins County
• Ithaca Pottery Site, an archaeological site in New York
• Ithaca, Ohio
• Ithaca, Wisconsin, a town
  • Ithaca (community), Wisconsin, in the town

• Ithaca High School (Michigan)
• Ithaca City School District, New York
  • Ithaca High School (Ithaca, New York)
• Ithaca College, New York

• Ithaka (play), a 1996 play by Botho Strauss
• "Ithaca" (Ulysses episode), an episode in James Joyce's novel Ulysses
• Ithaca (poem), a poem by Constantine P. Cavafy
• Ithaca, California, the setting for William Saroyan's novel The Human Comedy
• Ithaca, a no-ship in the Dune fictional universe
• Ithaka, a young-adult novel by Adèle Geras

• Ithaca (film), a 2015 American film
• Project Ithaca, a 2019 sci-fi film by Anthony Artibello and Kevin C. Bjerkness
• Ithaka (film), a 2021 Australian documentary film about the campaign to free Julian Assange

• Ithaca (Paula Cole album), 2010
• Ithaca (Barry Guy, Marilyn Crispell, and Paul Lytton album), 2004
• "Ithaca", a song by Peter Mulvey from Glencree, 1999
• Ithaca (band)

• Ithaca Bus Station, a former bus terminal in Ithaca, New York
• Ithaca Central Railroad, a shortline railroad
• Ithaca station (Lehigh Valley Railroad), a former railroad station
• Ithaca Tompkins International Airport (ITH)

• Ithaka (artist), American musician, writer, and artist
• Ithaka Maria (born 1979), Estonian singer and songwriter
• Craig Horner (born 1983), Australian actor and musician who has recorded as Ithaca

• Ithaka Harbors, publisher of academic journals in JSTOR
• 1151 Ithaka, an asteroid
• Ithaca Chasma, a valley on Saturn's moon Tethys
• Ithaca Gun Company, a US shotgun and rifle manufacturer
• Ithaca InterSystems, a defunct microcomputer manufacturer
• SS Ithaka, a shipwreck near the port of Churchill, Manitoba, in Hudson's Bay

• All pages with titles beginning with Ithaca