Look up Onchestus in Wiktionary, the free dictionary.
Onchestus may refer to:
- Onchestus or Onchestos, Greek town in ancient Boeotia northwest of Thebes
- Onchestus (river), river of ancient Thessaly, Greece
- Onchestus (phasmid), genus of insect
- Onchestus rentzi, Australian species of stick insect