- O’Brien, Darcy
- O’Brien, Flann
- O’Connor, Flannery
- O’Flaherty, Liam
- O’Henry
- O’Squarr, Flor
- Odóievski, Vladímir
- Olgoso, Ángel
- Oliphant, Margaret
- Olmos, Alberto
- Onetti, Juan Carlos
- Onfray, Michel
- Ono, Sokyo
- Ordine, Nuccio
- Orejudo, Antonio
- Ortega, Jesús
- Ortiz, Miguel Ángel
- Orwell, George
- Otte, Max
