| Name | Color | Sex | Year of birth | Microchip | Sire | Dam | Breed | Breeder |
|---|---|---|---|---|---|---|---|---|
| Thalestrice | br. | f | 1813 | Thoroughbred | Great Britain | |||
| Thalia | d.-bay | f | 1888 | Thoroughbred | Great Britain | |||
| Thames Haven | br. | f | 1900 | Childwick | Thames Valley | Thoroughbred | Great Britain | |
| Thames Valley | bay | f | 1896 | Hampton | Rosy Brook | Thoroughbred | Great Britain | |
| Thank You Marylou | chestnut | f | 2011 | Birdstone | Menifeeque | Thoroughbred | USA | |
| Thankful Blossom | bay | f | 1891 | The Apple | Thoroughbred | Great Britain | ||
| Thanks Pal | d.-bay | f | 1986 | Foolish Pleasure | O K Pal | Thoroughbred | USA | |
| Thanks to Tony | d.-bay | c | 1977 | Naskra | Nursey | Thoroughbred | USA | |
| Tharp | c | Thoroughbred | ||||||
| That's a Nice | chestnut | c | 1974 | Hey Good Lookin | Our Bonnie S. | Thoroughbred | USA |