Quotation authors by 'O'
| Full name | Nationality | Profession |
|---|---|---|
| Adam Oates | Canadian | Athlete |
| Adam Osborne | Author | |
| Adam Ostrow | American | Businessman |
| Adepero Oduye | American | Actress |
| Agnes Obel | Danish | Musician |
| Al Oerter | American | Athlete |
| Alexander Dale Oen | Norwegian | Athlete |
| Alexis Ohanian | American | Businessman |
| Alice Oswald | British | Poet |
| Amos Oz | Israeli | Writer |
| Ana Ortiz | American | Actress |
| Andres Manuel Lopez Obrador | Mexican | Politician |
| Andrew Oliver | American | Politician |
| Angel Olsen | American | Musician |
| Ann Oakley | British | Sociologist |
| Apolo Ohno | American | Athlete |
| Aristotle Onassis | Greek | Businessman |
| Ashley Olsen | American | Actress |
| Barack Obama | American | President |
| Barbara Olson | American | Journalist |