- Hiroko Oe
- Godwin Okafor
- Conor O'Kane
- Peter O'Kane
- Ivan Okhotnikov
- Duygu Okten
- Osikhuemhe Okwilagwe
- John Oliver
- Louise Oliver
- Gail Ollis
- Mary O'Malley
- Funmi Omotade
- Emeka Onwukamuche
- May Ooi
- Claudy Op Den Kamp
- Michael O'Regan
- Edvard Orlic
- Tim Orman
- Gaye Orr
- Sae Oshima
- Hanaa Osman
- Helen O'Sullivan
- Alex Otto
- Billur Ozgul