- Okaloo
- Okeechobee
- Okeelanta
- Okomo Mobile Home Park
- Old Amelia Mobile Home Park
- Old Bay View
- Old Bayshore Point
- Old Bridge Village Mobile Home Park
- Old Callaway
- Old Dan Mangrove
- Old Dinner Island
- Old Duette
- Old Fashioned Acres
- Old Fernandina
- Old Fort Trailer Park
- Old Grove
- Old Henley Place
- Old Hickery
- Old Hillsborough Estates
- Old Marco Junction
- Old Myakka
- Old Rhodes Key
- Old Town
- Old Town Hammock
- Oldsmar
- Oldsmar Farm
- Olga
- Olin's Mobile Home Park
- Olive
- Oliver Acres