| Obliteration | Keeneland,
06-Oct-25 |
| Obliviate | Dalby,
25-Apr-15 |
| OBLIVIATOR | Bassett Park,
28-Aug-10 |
| Oblivion | Sunshine Coast,
23-Mar-25 |
| Oblong Song | Wolverhampton,
13-Nov-22 |
| OBOE D'AMOR | |
| Oboe Soprano | Valparaiso Sporting Club,
31-Oct-23 |
| Oborozukiyo | Kanazawa,
24-Dec-24 |
| Obotchama | Chukyo,
22-Sep-24 |
| Oboy | Charles Town,
02-Aug-24 |
| Obra Clasica | San Isidro,
20-Apr-25 |
| Obra De Arte | Club Hipico Santiago,
22-Mar-25 |
| Obra Maestra | Kyoto,
04-Oct-25 |
| Obra Prima | Sapporo,
06-Sep-25 |
| Obrigada | Saratoga,
17-Aug-24 |
| Obrigado | Te Aroha,
21-Sep-25 |
| Obrigato | bet365 Park Kyneton,
06-Dec-18 |
| Obscene | Taree,
17-Aug-21 |
| Obscenity | Curragh,
22-Oct-25 |
| Obscentino | Northam,
06-Nov-25 |
| Obscura | bet365 Geelong,
26-Dec-20 |
| Obscure | Hawkesbury,
21-Nov-24 |
| Obscured By Clouds | Penn National,
09-Nov-23 |
| Obsequiada | San Isidro,
29-Jun-23 |
| OBSERVE | |
| Observed | Taree,
01-Jul-18 |
| Observer | Flemington,
01-Nov-25 |
| Obsess | Nantes,
19-Oct-24 |
| Obsessed With You | Emerald Downs,
07-Sep-25 |
| Obsessedwithyou | Sedgefield,
09-Oct-25 |
| Obsessing | Sportsbet-Pakenham,
10-Nov-23 |
| Obsession | Nowra,
23-Jul-23 |
| Obsessions | Grafton,
01-Dec-19 |
| Obsessive Maid | Horsham,
22-Mar-24 |
| Obsessive Nature | Narrandera,
22-Mar-25 |
| OBSESSIVE ZHENG | Moruya,
27-Nov-10 |
| Obsidhian | Tokyo,
11-Oct-25 |
| Obsidian | Vaal,
14-Aug-25 |
| Obsidian Dream | Kempton,
30-Mar-25 |
| Obsidian Knight | Lingfield,
31-Aug-25 |
| Obsidian Rose | Ipswich,
18-Jan-24 |
| Obsidian Storm | Los Alamitos Racecourse,
27-Oct-25 |
| Obsidian Verse | Goodwood,
12-Oct-25 |
| Obsidiana | Sonoda,
08-Oct-25 |
| Obsolete | Tatura,
20-Nov-18 |
| Obstinate Lass | Newcastle,
08-Aug-15 |
| Obstination | Pinjarra Park,
23-Jul-20 |
| Obstreperous | Colonial Downs,
12-Sep-25 |
| Obstructionist | Eagle Farm,
20-Sep-25 |
| Obtain | Wolverhampton,
06-Jun-23 |
| Obtusa | Kanazawa,
13-Apr-25 |
| Obtuse | San Isidro,
23-Apr-23 |
| OBUASI | |
| Obucci | Bendigo,
29-Oct-25 |
| Obverse | Sale,
23-Apr-24 |
| Obvious | Caulfield,
15-Oct-25 |
| Obvious | Golden Gate Fields,
04-Nov-23 |
| Obvious Agenda | Horseshoe Indianapolis,
31-Oct-25 |
| Obvious Conclusion | Lone Star Park,
14-Jul-25 |
| Obvious Icon | Wagga Riverside,
18-Oct-25 |