| Name | Color | Sex | Year of birth | Microchip | Sire | Dam | Breed | Breeder |
|---|---|---|---|---|---|---|---|---|
| Who's That Girl | chestnut | f | 1971 | Buckpasser | Napalm | Thoroughbred | USA | |
| Who's To Know | bay | f | 1970 | Fleet Nasrullah | Masked Lady | Thoroughbred | USA | |
| Whobabydatiz | bay | f | 2001 | Boston Harbor | Proud Encore | Thoroughbred | USA | |
| 4860-6 Whodatfleetkat | bay | f | 2012 | Afleet Alex | Headed Home | Thoroughbred | USA | |
| Whoopee | f | 1958 | Anwar | Sea Gipsy | Thoroughbred | Great Britain | ||
| 3473-5 Whooshka | bay | f | 2006 | 985101045089158 | Smart Strike | Bushra | Thoroughbred | USA |
| Whow | d.-bay | f | 1985 | Spectacular Bid | Hooplan | Thoroughbred | USA | |
| Why So Much | chestnut | f | 1987 | Northern Baby | Satiety | Thoroughbred | USA | |
| Whynot | br. | c | 1816 | Thoroughbred | Great Britain | |||
| Whynot | bay | c | Fenwick Barb | Royal Mare | Thoroughbred | Great Britain |