| Orton Park | Wagga,
13-Aug-23 |
| Orts Dream | Will Rogers Downs,
03-May-23 |
| Ortu Solis | Funabashi,
01-Oct-25 |
| Ortum Krisp | Port Hedland,
03-Aug-25 |
| Ortus | Saratoga,
22-Aug-25 |
| Ortus Glow | Funabashi,
04-Nov-25 |
| Oruanui Eruption | Geraldton,
13-Oct-13 |
| Orvassa | Ladbrokes Park Hillside,
15-Mar-17 |
| Orvieto | Sandown Hill,
27-Sep-14 |
| Orville B | Thistledown,
28-Aug-25 |
| Orville's Map | Churchill Downs,
01-Nov-25 |
| Orwell | bet365 Park Kyneton,
12-Oct-21 |
| Orwell | Urawa,
20-Aug-25 |
| Oryx | Gosford,
29-May-25 |
| Oryx Hustler | Kilbeggan,
13-May-23 |
| Orzala | Newcastle,
15-Sep-23 |
| Orzo | Kempton,
16-Nov-23 |
| Osa | Laurel Park,
12-Oct-25 |
| Osage Creek | Santa Anita,
15-Jun-25 |
| Osage Express | Remington Park,
17-Aug-25 |
| Osage Josy | Remington Park,
30-May-25 |
| Osaka | Te Rapa,
06-May-23 |
| Osaka Girl | Te Rapa,
31-Jan-24 |
| Osaka Miss | Gold Coast Poly,
20-Jul-24 |
| Osaka Sun | Gosford,
19-Dec-12 |
| Osaka Sunset | Barcaldine,
10-Jun-23 |
| Osaki Flower | Mizusawa,
26-Dec-23 |
| Osaki Thunder | Ohi,
23-Oct-25 |
| Osaki Wonder | Mizusawa,
30-Jun-25 |
| Osambashi | Sonoda,
16-Nov-23 |
| Osamu | Flemington,
08-Mar-25 |
| Osaxalina | Compiegne,
07-May-25 |
| Osaycan | Aquis Park Gold Coast,
04-Sep-21 |
| Osbaldo Lucky Boy | Ruidoso Downs,
07-Jul-25 |
| Osbaldoperfection | Sunland Park,
16-Feb-25 |
| Osbin | Mountaineer,
10-Jul-25 |
| Osborne | Hobart,
11-Jul-18 |
| Osborne Bulls | Royal Randwick,
05-Oct-19 |
| Osbourne | Churchill Downs,
04-May-25 |
| OSCA ERIC | |
| Oscar | Woodville,
30-Apr-25 |
| Oscar | Stony Creek,
13-Mar-11 |
| Oscar | Clairefontaine,
11-Jul-24 |
| Oscar Award | Gulfstream,
10-Dec-23 |
| OSCAR BAY | |
| Oscar Booie | Bowen,
16-Sep-25 |
| Oscar Bound | Belmont At The Big A,
03-Oct-25 |
| Oscar Brain | Morioka,
20-May-25 |
| Oscar Brave | Hanshin,
09-Dec-23 |
| Oscar Bravo | Mackay,
27-May-24 |
| Oscar Charlie | Kalgoorlie,
02-Oct-25 |
| Oscar Couronne | Tokyo,
22-Apr-23 |
| Oscar D | Horseshoe Indianapolis,
10-Sep-25 |
| Oscar De Teillee | Craon,
25-Sep-23 |
| Oscar Doctor | Narrogin,
04-Mar-10 |
| Oscar Doodle | Chelmsford City,
10-Jan-25 |
| Oscar Eclipse | Keeneland,
25-Oct-25 |
| Oscar Elite | Ayr,
22-Apr-23 |
| Oscar Gaze | Delaware Park,
23-May-25 |
| Oscar Glory | Sha Tin,
16-Jul-23 |