| Name | Color | Sex | Year of birth | Microchip | Sire | Dam | Breed | Breeder |
|---|---|---|---|---|---|---|---|---|
| Thirty-Third | chestnut | f | 1902 | Thoroughbred | USA | |||
| Thirtysomething | chestnut | f | 1993 | Thirty Six Red | Athenia | Thoroughbred | USA | |
| This is War | d.-bay | f | 2012 | War Front | Ask Me When | Thoroughbred | USA | |
| Thislillightofmine | bay | f | 1997 | Kingmambo | Minnie Hauk | Thoroughbred | USA | |
| Thisonesforricky | bay | f | 2009 | Empire Maker | Fabulous Ballet | Thoroughbred | USA | |
| Thixendale | chestnut | f | 1938 | Caerleon | Thoroughbred | Great Britain | ||
| Thong | bay | f | 1964 | Nantallah | Rough Shod II | Thoroughbred | Great Britain | |
| Thor | bay | c | 1930 | Ksar | Lasarte | Thoroughbred | France | |
| Thora | f | 1954 | Asterios | Thusnelda | Thoroughbred | Germany | ||
| Thora | bay | f | 1878 | Longfellow | Susan Ann | Thoroughbred | USA |