| Author Name | Profession | Nationality |
| Oded Fehr | Actor | Israeli |
| Odysseas Elytis | Writer | Greek |
| Oksana Baiul | Athlete | American |
| Olafur Eliasson | Artist | Danish |
| Oliver Evans | Inventor | American |
| Oliver Hardy | Actor | American |
| Oliver Kahn | Athlete | German |
| Oliver St. John | Statesman | English |
| Olivia De Havilland | Actress | American |
| Omar Epps | Actor | American |
| Omar Khayyam | Poet | |
| Oriana Fallaci | Journalist | Italian |
| Orlando A. Battista | ||
| Orlando Cepeda | ||
| Orlando Gibbons | Composer | English |
| Orlando Jones | Comedian | American |
| Orrin Hatch | Politician | |
| Orson Scott Card | Writer | American |
| Osama Bin Laden | Criminal | |
| Osbert Lancaster | Cartoonist | English |
| Oscar Hammerstein | Writer | American |
| Oscar Hammerstein Ii | Musician | American |
| Ossie Davis | Actor | American |
| Otto Bauer | Writer | Austrian |
| Otto Hahn | Scientist | German |
| Otto Hermann Kahn | Businessman | German |
| Otylia Jedrzejczak | Athlete | Greek |
| Owen Feltham | Author | British |
| Owen Glendower | Royalty | Welsh |
| Owen Hart | Entertainer | Canadian |
