"O" Bobs
- Roberta Oaks - Clothing Designer
- Bob O'Brien - Baseball
- Robert O'Brien - Artist
- Robert C. O'Brien - Author
- Robert O'Brien - Studio Executive
- Robert O'Brien - British Military
- Robert O'Brien - Lawyer
- Robert O'Brien - Motor Sports
- Robert O'Brien - Canoeist
- Bob Odenkirk - Actor
- Bob Ojeda - Baseball
- Bobby Olive - Football
- Bob Oliver - Baseball
- Robert Olmstead - Author
- Robert O'Neill - US Navy Seal
- Robert Opel - Photographer
- Robert Oppel - Actor
- Bobby Ore - Stunt Driver
- Robert Orme - British Military
- Robert Orme - Historian
- Robert Ormerod - Photographer
- Bobby Orr - Jazz Drummer
- Robert Orr - Business
- Robert Orr - Pennsylvania Senate
- Bobby Orr - Hockey
- Robert C. Orr - United Nations
- Robert D. Orr - Indiana Governor
- Robert F. Orr - North Carolina Supreme Court
- Robert K. Orr - Composer
- Robert T. Orr - Biologist
- Robert Osborne - Actor
- Bobby Osborne - Bluegrass
- Roberto Osuna - Baseball
- Robert Otto - Artist
- Bob Ottum - Journalist
- Robert Owen - Artist
- Rob Owen - Journalist
- Robert Owen - Social Reformer
- Robert Owen - Australian Politician
- Robert Owen - Theologian
- Robert Owen - Canoeist
- Robert Owen - Darts
- Robert D. Owen - US House
- Robert L. Owen - Engineer
- Robert L. Owen - US Senate
- Robert M. Owen - British Judge
- Robert Owens - Songwriter
- Bob Owens - Football
- Robert A. Owens - Business
- Robert A. Owens - Medal of Honor Recipient
- Robert B. Owens - Engineer
- Robert L. Owens - Composer
- Robert M. Owens - Lawyer