IMO or Imo may refer to:

Maritime

  • International Maritime Organization
  • IMO number, a unique identity number issued to seacraft (pattern "1234567")
  • SS Imo, a 1889 ship involved in the Halifax Explosion

Meteorology

  • International Meteorological Organization
  • Icelandic Meteorological Office

Other

  • Irish Medical Organisation
  • Intelligent Medical Objects, a privately held company specializing in medical vocabularies
  • Isomaltooligosaccharide, a mixture of short-chain carbohydrates which has a digestion-resistant property
  • Idiopathic Massive Osteolysis, a name for Gorham's disease, a rare bone disease
  • International Mathematical Olympiad
  • International Meteor Organization
  • Imo State, Nigeria
  • imo.im, a video calling and instant messaging app
  • IMO (in my opinion), an Internet slang expression