| Oversize | Albury,
24-Feb-25 |
| Overspeed | Goulburn,
30-Oct-09 |
| Overspent | Delaware Park,
16-Oct-25 |
| Overstand | Niigata,
19-Oct-25 |
| Overstate | Dundalk,
27-Jan-24 |
| Overstate | Ellerslie,
25-May-25 |
| Overstated | Balaklava,
09-Jul-25 |
| Overstatement | Ipswich,
24-May-17 |
| Overstatement | Keeneland,
09-Oct-25 |
| Overstay | Moe,
24-May-18 |
| Overstep | Moonee Valley,
25-Aug-18 |
| Overstep | Aqueduct,
25-Feb-24 |
| Overstrike | Murray Bridge Gh,
24-May-25 |
| Oversubscribed | Happy Valley,
04-Jul-24 |
| Oversubscribed | Aqueduct,
09-Nov-24 |
| Overtaker | Grafton,
09-Apr-24 |
| Overtaker | Sonoda,
11-Jun-25 |
| Overtaxed | Gulfstream,
05-Jun-23 |
| Overtern | Bundaberg,
06-Sep-25 |
| Overthebluesky | Philadelphia Park,
05-Sep-23 |
| Overtheline | Newbury,
03-Nov-22 |
| Overthetopjustice | Horseshoe Indianapolis,
24-May-24 |
| Overthought | Ascot,
06-May-23 |
| Overthought | Fairmount Park,
04-Oct-23 |
| Overthrow | Swan Hill,
03-Aug-23 |
| Overthrows | |
| Overtime Charlie | Presque Isle Downs,
17-Jun-25 |
| Overtome | Wangaratta,
27-Oct-25 |
| Overton Onyx | Colac,
12-Feb-17 |
| Overton Window | TRIAL Rosehill Gardens,
22-Mar-22 |
| Overtone Aria | Sunshine Coast,
18-May-14 |
| Overtoux | Wangaratta,
15-May-25 |
| Overtrick | Pukekohe Park,
16-Oct-24 |
| Overture | Thoroughbred Park,
21-Feb-10 |
| Overture | Pontefract,
22-Jun-25 |
| Overview | Eagle Farm,
02-Oct-24 |
| Overwatch | Cairns,
23-Aug-25 |
| Overwish | Laurel Park,
07-Oct-24 |
| Overwrite | Ohi,
22-Sep-23 |
| OVERWROUGHT | |
| Oveta's Hobby | Santa Anita,
18-Oct-25 |
| Oviate | Bunbury,
09-Mar-14 |
| Oviatt Class | Colonial Downs,
14-Sep-25 |
| Ovid | Thistledown,
10-Oct-25 |
| Ovidius | Doomben,
08-Feb-25 |
| Ovidstown Hill | Sligo,
08-Aug-25 |
| Oviedo | Newbury,
24-Oct-25 |
| Ovoid | Townsville,
06-Mar-25 |
| Ow Ah McGrath | Clifford Park,
30-Apr-10 |
| Ow Celereese | Hawera,
10-Aug-25 |
| Owari | Warwick Farm,
22-May-24 |
| OWATA STASH | Alexandra,
08-Jan-11 |
| Owe You Nothing | Saga,
18-Aug-24 |
| Owe You One | Charles Town,
26-Jul-24 |
| Owen Almighty | Keeneland,
19-Oct-25 |
| Owen Barows | Mizusawa,
05-Sep-23 |
| Owen County | Kembla Grange,
04-Oct-25 |
| Owen Hunt | San Isidro,
03-May-25 |
| Owen Jeep | Club Hipico Santiago,
08-Apr-25 |
| Owen Little | Wolverhampton,
20-Jul-23 |