- O. Schmidt Ricardo De
- Obrovac Marko
- Ocampo Andrés F.
- Odusami Modupe O.
- Odusanya Kayode A.
- Ofori-Amanfo Joshua
- Ogbuji Bibian
- Oikonomou George
- Oinas-Kukkonen Harri
- Oiwa Yutaka
- Ojiako Uchenna
- Okabe Daisuke
- Okamoto Eiji
- Oklander Boris
- Okonor Obinna
- Olanrewaju Abdus-Samad Temitope
- Oldenbeuving Ruud M.
- Oliveira Fábio
- Oliveira Luciana Pereira
- Oliveira Manuel
- Oliveira Rui
- Oliveira Rui
- Oliver Miquel
- Olivereau Alexis
- Oller Antoni
- Olowe Victor
- Olsen Dag H.
- Olsen Petur
- Olstad Hege Annette
- Ometov Aleksandr
- Ometov Aleksandr
- Ometov Aleksandr
- Ometov Aleksandr
- Omicini Andrea
- Ongenae Femke
- Ongenae Veerle
- Onofrei George
- Opland Leif Erik
- Oprescu Ana-Maria
- Oprescu Iuniana
- Oredo John
- Oren Gal
- Oriat Catherine
- Orlić Marin
- Orlov Yuri
- Orosz Mihály
- Ortega Carlos
- Ortiz Jorge E.
- Ortmeier Frank
- Ortín Jorge
- Oruç Sercan
- Oruç Sertaç
- Osakwe Christian Nedu
- Osipov Evgeny
- Ospina Juan P.
- Ott Jörg
- Otterstad Christian
- Ottow Christiaan
- Ottoy Geoffrey
- Ouadou Mohamed
- Ouffoué Georges
- Owe Olaf
- Owe Olaf
- Owezarski Philippe
- Owusu Acheampong
- Owusu Acheampong
- Oya Makoto
- Oyedare Taiwo
- Ozanne Alain
- Ozdem Ozen Okat
- Ozkasap Oznur
- Ošlejšek Radek
- O’connor Peter
- O’regan Nicholas