O
- O Charmeil
- O D Reddy
- O G Soni
- O Goswami
- O J Bansal
- O J Simpson
- O N Singh
- O P Adukia
- O P Agarwal
- O P Bagla
- O P Bharadwaraj
- O P Bhatt
- O P Bubna
- O P Chawla
- O P Dhanuka
- O P Garg
- O P Goyal
- O P Gupta
- O P Jagetiya
- O P Kakkar
- O P Khaitan
- O P Khanna
- O P Khetan
- O P Lohia
- O P Makkar
- O P Mathur
- O P Mehra
- O P Modi
- O P Munjal
- O P Pacheria
- O P Roongta
- O P Sahni
- O P Setia
- O P Sharma
- O P Singhi
- O P Vaish
- O P Yadav
- O Ravi
- O S Agarwal
- O Swaminatha Reddy
- O V Bundellu
- O V Kuruvilla
- O. Henry
- O. N. Dhar
- O. P. Jindal
- O. P. Ramaswamy Reddiyar
- O. Panneerselvam
- O. Rajagopal
- O. T. Lepcha
- O. V. Alagesan
- O.D. (musician)
- O.J. Atogwe
- O.J. Mayo
- O.J. Santiago
- Oakie Doke
- Oakley Hall
- Obadele Thompson
- Obafemi Ayanbadejo
- Obafemi Martins
- Obama Girl
- Obed Asamoah
- Obert Mpofu
- Obina
- Obinna Nwaneri
- Oburu Odinga
- Octavia Butler
- Octavia E. Nasr
- Octavio Carlin
- Octavio Dotel
- Octavio Paz
- Odalis Perez
- Oded Fehr
- Odell Thurman
- Oderick Turner
- Odetta (musician)
- Odette Yustman
- Odil Ahmedov
- Odile Gilbert
- Odwa Ndungane
- Ofer Nimrodi
- Ogden Nash
- Ogemdi Nwagbuo
- Ognjen Vukojevic
- Ogonna Nnamani
- Oguchi Onyewu
- Oh Beom-Seok
- Oh Se-hoon
- Oil Can Boyd
- Ojo Maduekwe
- Oka Nikolov (footballer)