- O'Donnell, Margaret
- O'Rance, Louise
- O'Reilly, Denis
- O'Reilly, Laurence
- Odello, Marco
- Office of Aboriginal Affairs Victoria
- Office of Evaluation and Audit
- Office of the Inspector of Custodial Services, Government of Western Australia
- Ogilvie, James
- Ogle, Greg
- Ogloff, James
- Omeri, Sheryn
- Ooi, Evarn
- Osborne, Brodrick
- Osborne, Howard
- Osborne, Katy
- Oscar, June
- Owen, Stuart