| Name | Color | Sex | Year of birth | Microchip | Sire | Dam | Breed | Breeder |
|---|---|---|---|---|---|---|---|---|
| Thidiot | chestnut | f | 1941 | Invermark | Fairy Ring | Thoroughbred | USA | |
| Thiella | bay | f | 1976 | Busted | Seaswan | Thoroughbred | Great Britain | |
| Thill | d.-bay | f | 1974 | Iron Ruler | Ta Wee | Thoroughbred | USA | |
| Thimble Island | bay | f | 1997 | Kissin Kris | Stellar Performer | Thoroughbred | USA | |
| Thin Novel | chestnut | f | 2004 | 985101026070560 | Noverre | The In-Laws | Thoroughbred | Great Britain |
| Thinghatab | f | 1980 | Al Hattab | Do Your Thing | Thoroughbred | |||
| Things Change | grey | f | 1996 | Stalwart | Romanticat | Thoroughbred | USA | |
| Thinking Cap | bay | c | 1952 | Rosemont | Camargo | Thoroughbred | USA | |
| Thiorba | br. | f | 1940 | Thoroughbred | France | |||
| Third Martini | bay | c | 1959 | Hasty Road | The Golden Girl | Thoroughbred | USA |