- DOO stands for Description Of Operation
- DOO stands for Director of Operations (various organizations)
- DOO stands for Driver Only Operation
- DOO stands for Department Organization Order
- DOO stands for Developer, Owner and Operator
- DOO stands for District Operations Office (US Navy)
- DOO stands for District Ordnance Officer (rank; US DoD)
- DOO stands for Department of Defense Originating Office (US DoD)
- DOO stands for Drustvo s Ogranicenom Odgovornoscu (Croatian: Limited Liability Company)
- DOO stands for Double Oven Oscillator (Symmetricom)
- DOO stands for Director of Oceanography Operations
- DOO stands for Days Overdue Outstanding
DOO