| Officer In Command | Greyville,
01-Nov-25 |
| Officer Of State | Plumpton,
20-Apr-25 |
| Officer Quigley | Fair Grounds,
25-Feb-24 |
| Officer Stone | Colonial Downs,
02-Sep-23 |
| Official Business | Turfway Park,
29-Mar-24 |
| Official Miracle | Taree,
05-Apr-14 |
| Official Secret | Bong Bong,
11-Nov-09 |
| Official Secret | Narrogin,
23-Dec-23 |
| Official Secret | Fairview,
04-Apr-25 |
| Officially Yours | Thistledown,
11-Oct-25 |
| Officiate | Flemington,
04-Oct-25 |
| Officio | Kembla Grange,
05-Nov-13 |
| Offlee Naughty | Del Mar,
23-Aug-24 |
| Offlee Tricky | Thistledown,
26-Jul-23 |
| Offley Special | Assiniboia Downs,
15-May-25 |
| Offline | Avondale,
06-Nov-25 |
| Offranville | ParisLongchamp,
12-Sep-24 |
| OFFSET PRINCE | Warwick,
26-Dec-14 |
| OFFSHORE | NMIT Ararat Park,
11-Feb-13 |
| OFFSHORE ACCOUNT | Scone,
08-Nov-11 |
| Offshore Affair | Tampa Bay Downs,
25-Nov-23 |
| Offshore Bandit | Sportsbet-Ballarat Synthetic,
24-Jul-23 |
| Offshore Girl | Sonoda,
16-Oct-25 |
| Offshore Tithe | Fair Grounds,
18-Dec-23 |
| OFFSIDER | |
| Offspring | Canberra,
18-Oct-24 |
| Offtap | Warracknabeal,
05-Jul-21 |
| Offthepeg | Canterbury,
12-May-09 |
| Offtheroadagain | Mahoning Valley,
28-Dec-24 |
| Offutt Cole | Mountaineer,
01-Oct-25 |
| Offwiththefairies | Toowoomba,
05-Dec-15 |
| Offy'scracker | Northam,
15-Sep-24 |
| Offyarocatwo | Bowraville,
25-Nov-23 |
| Offyarocka | Toowoomba Cushion Track,
20-Apr-13 |
| Oficial Maharaja | Palermo,
04-Nov-23 |
| Oforawesome | Mackay,
20-Mar-15 |
| Often Away | Morphettville Parks,
28-Jul-11 |
| Often Enough | Thistledown,
24-Apr-24 |
| Often Overlooked | Lingfield,
21-Feb-23 |
| OFTEN WRONG | Clifford Park,
30-Oct-10 |
| Oftheworld | Dieppe,
01-Jul-23 |
| Ofukumame | Kyoto,
05-Oct-25 |
| Ofuton | Kanazawa,
15-Jul-24 |
| Og Kissing Bandit | Remington Park,
26-May-25 |
| Og Sin City | Will Rogers Downs,
14-Oct-25 |
| Ogallala | Zia Park,
04-Nov-25 |
| Ogaru | Mombetsu,
03-Nov-25 |
| Ogatan | Moe,
12-Jul-24 |
| Ogee | Gowran Park,
30-Sep-23 |
| Ogema Bay | Turfway Park,
20-Dec-24 |
| Ogenblik | Niigata,
22-Oct-22 |
| Oggie | Dalby,
31-Aug-19 |
| Oggle | TRIAL Lark Hill,
08-Sep-14 |
| Ogifushino Chikai | Mombetsu,
12-Aug-25 |
| Ogilvie | Broadmeadow,
24-Jun-10 |
| Ogino Kaname | Tokyo,
01-Nov-25 |
| Ogino Mai | Mombetsu,
03-May-23 |
| Ogle | Walcha,
09-Feb-01 |
| Oglethorpe | Saratoga,
15-Jul-23 |
| Ogo | Casino,
30-May-25 |