| Name | Color | Sex | Year of birth | Microchip | Sire | Dam | Breed | Breeder |
|---|---|---|---|---|---|---|---|---|
| Washington Bridge | bay | f | 2007 | Yankee Gentleman | Stirling Bridge | Thoroughbred | USA | |
| Washington Capital | chestnut | c | 2024 | 981020057083013 | Improbable | Veruschka | Thoroughbred | Brandywine Farm (Jim & Pam Robinson) |
| Washoe Belle | br. | f | 1913 | Sweep | Grace Commoner | Thoroughbred | USA | |
| Wasnah | bay | f | 1987 | Nijinsky II | Highest Trump | Thoroughbred | USA | |
| Wasp | bay | f | 1811 | Gohanna | Thoroughbred | Great Britain | ||
| Wassl | bay | c | 1980 | Mill Reef | Hayloft | Thoroughbred | Great Britain | |
| Wasted Tears | d.-bay | f | 2005 | Najran | Wishes and Roses | Thoroughbred | USA | |
| Wastells Turk | c | 1690 | Thoroughbred | |||||
| Wasthi | bay | f | 1887 | Thoroughbred | France | |||
| Watch | chestnut | f | 1997 | Lord At War | Watch the Time | Thoroughbred | USA |