- Oberoi Sundeep
- Obersteller Hannah
- Ocello Alberto
- Ochoa Martín
- Ochola Elisha
- Ocloo Charles Mawutor
- Oda Tetsuhisa
- Oers Matthijs Van
- Oftedal Erlend
- Ogawa Satoshi
- Oh Hakjoo
- Oh Hyunok
- Oh Jaesang
- Ohki Tetsushi
- Ohkubo Miyako
- Ohsuga Akihiko
- Oikonomou George
- Oikonomou George
- Ojo Adegboyega
- Okada Hiroki
- Okada Kenichi
- Okhravi Hamed
- Okolica James
- Oleshchuk Vladimir
- Olimid Ruxandra Florentina
- Olislaegers Sandra
- Oliveira Anderson De
- Oliveira Daniela
- Oliveira Tiago
- Oliver Paula
- Olivier Martin
- Olivier Martin
- Omote Kazumasa
- Ong Toan
- Onieva Jose A.
- Onolaja Olufunmilola
- Onut Iosif Viorel
- Ooms Merel
- Oostdijk Martijn
- Oosterman Jasper
- Ophoff Jacques
- Ophoff Jacques
- Ophoff Jacques
- Orthacker Clemens
- Ortmeier Frank
- Ortolani Stefano
- Osborne Grant
- Oswald David
- Oswald Elisabeth
- Othman Hussien
- Othmane Lotfi Ben
- Otterbein Thomas
- Ottoy Geoffrey
- Ou Changhai
- Ouahla Nouha
- Overdorf Rebekah
- Overill Richard
- Overill Richard
- Owe Olaf
- Oyelami Oluwasayo
- Oyelami Oluwasayo
- Ozga Wojciech
- Ozmen Muslum Ozgur
- Ošťádal Radim
- O’hara Kieron
- O’keefe Christine M.
- O’regan Jim
- O’shaughnessy Stephen
- O’sullivan Pádraig