Nickname with O
- Olive
- Ozzy
- Oli
- Otto
- Ozzie
- Oliver
- Olli
- Opie
- Omar
- Olivia
- oscar
- Owen
- Oldie
- Olaf
- Osito
- Oma
- Otter
- Oso
- Omi
- Otis
- Ola
- Ogre
- old man
- Opa
- oreo
- Odie
- opal
- Ori
- Obi
- Orlando
- Oddball
- Oni
- Oppie
- Olga
- Oppa
- Obie
- Old man
- Opi
- oompa loompa
- Orly
- Oliv
- Orion
- Oppy
- Oak
- Ona
- Old fart
- Ole
- oprah
- Ovi
- Oggie
- Octo
- Old lady
- Oldy
- oggy
- Owl
- Ottie
- Owie
- Omega
- oslo
- OMG
- octopus
- Oddy
- Ophelia
- Old boy
- Oswald
- Oddie
- Onion
- Ody
- Oh baby
- Olivier
- Ossie
- Okie
- Ossi
- ossy
- Osky
- Ora
- Orange man
- Old Sport
- Obelix
- OLLY
- Odin
- Oaf
- one and only
- oger
- Oct
- Oscar the Grouch
- Otty
- oly
- Odd ball
- oman
- oops
- Odi
- Osi
- Oti
- osvaldo
- Obby
- O-man
- Old timer
- osh
- One
The words in the list Nickname with O come from players of the word game City, Country, River.