| Onondaga Golf and Country Club | Fayetteville | New York |  United States of America | inactive |
| Onsjö Golfklubb | Vänersborg | Västra Götaland |  Sweden | inactive |
| Onsøy Golfklubb | Manstad | Østfold |  Norway | inactive |
| Ontake | Kani | Gifu |  Japan | inactive |
| Ontario Country Club | Ontario | New York | United States of America | inactive |
| Onteora Club | Tannersville | New York | United States of America | inactive |
| Ontonagon Golf Course | Ontonagon | Michigan | United States of America | inactive |
| Onuma Kokusai Country Club | Kayabe | Hokkaido | Japan | inactive |
| Onuma Lake Golf Club | Kayabe | Hokkaido | Japan | inactive |
| Onward Mangilao Golf Club | Mangilao | Guam |  Guam | inactive |
| Onward Talofofo Golf Club | Talafofo | Guam | Guam | inactive |
| Onwentsia Club | Lake Forest | Illinois | United States of America | inactive |
| Onyx | Grand Blanc | Michigan | United States of America | inactive |
| Oodate Country Club | Oodate | Akita | Japan | inactive |
| Ooka Golf Club | Kinosaki | Hyogo | Japan | inactive |
| Oonodai Golf Club | Akita | Akita | Japan | inactive |
| Oosaki Golf Club | Shida | Miyagi | Japan | inactive |
| Oost-Zuid | Nunspeet | Gelderland |  Netherlands | inactive |
| Oost-Zuid | Groesbeek | Gelderland | Netherlands | inactive |
| Oostwoud-Westwoud | Benthuizen | Zuid-Holland | Netherlands | inactive |
| Ootacamund Gymkhana Golf Club | The Nilgiris | Tamil Nadu |  India | inactive |
| Ootaka | Housu | Ishikawa | Japan | inactive |
| Ootawara Golf Club | Nasu | Tochigi | Japan | inactive |
| Ooyodogawa Golf Course | Miyazaki | Miyazaki | Japan | inactive |
| Opal Cove Resort Golf Course | Coffs Harbour | New South Wales |  Australia | inactive |
| Open | Cotgrave | Nottinghamshire |  England | inactive |
| Open | Dongguan | Guangdong |  China | inactive |
| Open | Fingal | Victoria | Australia | inactive |
| Open 9 | Myrtle Beach | South Carolina | United States of America | inactive |
| OPEN GOLF St. Johann Alpendorf | Sankt Johann im Pongau | Salzburg |  Austria | inactive |
| Open Golf Zandvoort | Zandvoort | Noord-Holland | Netherlands | inactive |
| Open.9 Golf Eichenried | Moosinning | Bavaria |  Germany | inactive |
| Openbare Golfbaan Kralingen | Rotterdam | Zuid-Holland | Netherlands | inactive |
| Openbare Golfclub Dronten | Dronten | Flevoland | Netherlands | inactive |
| Oporto Golf Club | Espinho | Beira Litoral |  Portugal | inactive |
| Opotiki Golf Club | Opotiki | Bay of Plenty |  New Zealand | inactive |
| Oppdal Golfklubb | Oppdal | Sør-Trøndelag | Norway | inactive |
| Oppegård Golfklubb | Oppegård | Akershus | Norway | inactive |
| Oppenheimer Golf Club | Welkom | Free State |  South Africa | inactive |
| Opunake Golf Course | Opunake | Taranaki | New Zealand | inactive |
| Oquirrh Hills Golf Course | Tooele | Utah | United States of America | inactive |
| Ora Country Club | Jeju | Jeju |  South Korea | inactive |
| Orange | Savoy | Illinois | United States of America | inactive |
| Orange | Parrish | Florida | United States of America | inactive |
| Orange | Anseong | Gyeonggi | South Korea | inactive |
| Orange | Tomioka | Gunma | Japan | inactive |
| Orange | Haga | Tochigi | Japan | inactive |
| Orange | Bryanston | Wiltshire | England | inactive |
| Orange | Lésigny | Ile-de-France |  France | inactive |
| Orange (Executive - Par 3) | Sankt Johann im Pongau | Salzburg | Austria | inactive |