Finn person fra Grefsen
- John Olaf Ofstad
- Andreas Ohldieck
- Ann-Eline Ohldieck
- Buangoen Olafsen
- Ida Emilie Olafsen
- Karin Bøler Olafsen
- Lillian Olafsen
- Marie Helene Olafsen
- Odd Rolf Olafsen
- Oddrun Olafsen
- Solveig Mjelstad Olafsrud
- Anne Olaisen
- Kristin Johanne Olaisen
- Cathrine Oland
- Mari Oland
- Dawid Jan Olbrys
- Marte Oldervoll
- Fredrik Oledal
- Vitalii Oliinyk
- Sidney Tyrone Oliver
- Anne-Sofie V Olsen
- Ann Helen Olsen
- Annlaug Marie Lien Olsen
- Ann-Torill Olsen
- Arild Olsen
- Arne Ivar Olsen
- Asta Edith Olsen
- Beate Katrin Olsen
- Beate Katrin Olsen
- Bjørn Henry Olsen
- Christian Dag Olsen
- Dagfinn Olsen
- Dag Rune Olsen
- Einar Wilhelm Olsen
- Eli Budsberg Olsen
- Erling Eugen Olsen
- Heidi H Olsen
- John Ingve Olsen
- Johnny Leo Olsen
- Jon Are Olsen
- Jorunn Olsen
- Kari Olsen
- Kenneth Olsen
- Magnus Schlichting Olsen
- Maja Zhang Olsen
- Marita Lien Olsen
- Morten Olsen
- Nicole Mimmi Martins Olsen
- Ole Gunnar Olsen
- Per Olav Olsen
- Per Robert Olsen
- Pål Rosén Olsen
- Pål-Espen Olsen
- Pål Magne Olsen
- Reidar Kaland Olsen
- Roy Olsen
- Solveig Marie Olsen
- Sophie Olsen
- Tronn Reidar Olsen
- Carl Enar André Olsson
- Viktor Olsson
- Sigmund Omang
- Siri Merete Omang
- Ellen Oma Nordstrøm
- Fatuma Omar
- Stine Ombustvedt
- Erik Omland
- Morten Omland
- Nina Elisabet Omland
- Anfani Omosele
- Marit Christine Opdahl
- Helene Margrethe Storebø Opheim
- Kari Opheim
- Vilde Nathalie Opheim
- Silje Viggen Opsahl
- Silje Langdal Opstad
- Silje Opstad
- Erlend Ormbostad
- Tone Ormbostad
- Tomas Manuel Osborne Gonzalez-Fabres
- Isabel Oskarsen
- Trine Oskarsen
- Said Osman
- Warda Ibrahim Osman
- Laura Osmani
- Eilif Ottar
- Asle Ottersen
- Ida Mathilde Ottersen
- Bente Orlaug Ottesen
- Oleg Anatoljevitch Oudovikov
- Anne Marit Oulie
- Bente Birgitte Oulie
- Erik Steffen Oulie
- Lillian Oulie
- Ragnhild Birgitte Oulie
- Tuva Heimdal Oulie
- Inge Ovesen
- Stian Ovesen
- Ole Torstein Ovrum