| 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 |
“But despite the universality of URLs, we often forget that they're not just a handy way to address network resources. They're also valuable communication tools.”
“How can smart women be so stupid about men sometimes? Lack of knowledge. It's what men have kept secret for so long.”