• O'Connell, Jack
• O'Connor, Brian
• O'Connor, Mary
• O'Connor, Patrick
• O'Connor, Patrick J.
• O'Donnell, Anthony J
• O'Donnell, Christine
• O'Keefe, Sean
• O'Malley, Martin
• O'Neal, Michael
• O'Neal, Mike
• O'Neil, Daniel
• O'Rourke, Jim
• Oakar, Mary Rose
• Oaks, Nathaniel T
• Obama, Barack
• Obama, Sr., Barack
• Obenshain, Mark D.
• Oberstar, James L
• Obey, David R.
• Obrador, Andres Manuel Lopez
• Oder, G. Glenn
• Odom, Gary
• Ogden, Steve
• Oliver, Kenneth N.
• Olmert, Ehud
• Olsen, Luther
• Olszewski, John A., Jr.
• Olszewski, John A., Sr.
• Onorato, George
• Onstad, Kenton
• Oppenheimer, Suzi
• Orban, Viktor
• Orszag, Peter
• Ortiz, Deborah
• Osborne, Tom
• Osterman, Harry
• Otter, Butch
• Ouattara, Alassane
• Ouyahia, Ahmed
• Oxley, Dennie
• Oxley, Michael G