| Name | Color | Sex | Year of birth | Microchip | Sire | Dam | Breed | Breeder |
|---|---|---|---|---|---|---|---|---|
| Third Party | br. | f | 1935 | Teddy | Thoroughbred | USA | ||
| 0546-4 Third Sacker | grey | c | 2001 | Maria's Mon | De La Cat | Thoroughbred | Canada | |
| Third Tuck | f | William The Third | Thoroughbred | |||||
| Thirsty Lady | bay | f | 2014 | Stay Thirsty | Flashy Frolic | Thoroughbred | USA | |
| Thirteen Tricks | bay | f | 2001 | Grand Slam | Talltalelady | Thoroughbred | USA | |
| Thirty Eight Paces | chestnut | c | 1978 | Nodouble | Thirty Paces | Thoroughbred | USA | |
| Thirty Paces | chestnut | f | 1973 | Dancing Count | Bank Book Sadye | Thoroughbred | USA | |
| Thirty Six Red | chestnut | c | 1987 | Slew O'Gold | Heartbreak | Thoroughbred | USA | |
| Thirty Years | bay | f | 1973 | Bold Hour | Battle of Roses | Thoroughbred | USA | |
| Thirty Zip | d.-bay | f | 1983 | Tri Jet | Sailaway | Thoroughbred | USA |