List of leading Thoroughbred racehorses

It is common to compare racehorses on multiple factors such as their overall race record, the quality of the horses they beat and the brilliance of their wins.

Jumpers tend to be older than their flat racing counterparts[6] and can have much longer careers, making it possible to earn a large number of wins.

For example, champion hurdler Hurricane Fly won a then-record 22 Grade One races over his ten-year career.

[8] In part because they may have longer racing careers, some of the most winning racehorses of all time are females, including Kincsem, Black Caviar, Winx, and Zenyatta.

[31] Nordlicht (chestnut horse 1941–1968, by Oleander x Nereide, by Laland) was also undefeated after an unknown number of starts.

Morston (colt by Ragusa x Windmill Girl by Hornbeam) had two starts, winning both, the second of which was the 1973 Epsom Derby.

[108] Don Juan by Loyalist, Ball's Florizel (1801), Mirza by the Godolphin Arabian, and Lecturer (1869), were also unbeaten, but the number of their wins is unknown.

[110] Condado, a chestnut horse who raced in Puerto Rico from 1936 to 1943, won a grand total of 152 times[111] Galgo Jr. earned 137 wins in 159 starts from 1930 to 1936.

[114] Pan Zareta started 151 times with 76 wins and is considered to be the "winningest female Thoroughbred in American history".

The following list considers horses that won grade one / group one races that were open for International competition.

Most of them raced (at least in part) in Japan, Hong Kong, Australia and/or Dubai due to large purse sizes.

[486] Where applicable, the conversion to US$ was made at the time the horse raced so does not reflect current exchange rates.

However, Curlin, Arrogate, Winx, Hokko Tarumae, Panthalassa, and Gun Runner descend instead from the Native Dancer sire line through Mr. Prospector.