• John O'Callaghan
• Michael O'Hanlon
• Michael O'Keefe
• Clare O'Neil
• Robert O'Neill
• Rolando Ochoa
• Tanya Ogilvie-White
• Hans J. Ohff
• Bob Olivier
• Zeyar Oo
• Malki Opatha
• Gonzalo Vázquez Orbaiceta
• Phil Orchard
• Andrew Orchard
• Jeffrey Ordaniel
• Sven Ortmann
• Yuma Osaki
• Alexander Osborne
• Gabriel Otis
• Djoomart Otorbaev
• Michael Outram
• Frank Owen
• Alan Oxley
• Mary-Louise O’Callaghan
• Sarah O’Connor
• Andrew O'Neil
• Simon O’Rourke
• Kate O’Shaughnessy
• Department of the Prime Minister and Cabinet