The title of champion, or leading, sire of racehorses in Great Britain and Ireland is awarded to the stallion whose offspring have won the most prize money in Britain and Ireland during the flat racing season. The current (2022) champion is Dubawi, who earned his first title after finishing runner-up multiple times.

Unlike the similar title for leading sire in North America, the stallion in question does not need to have resided in Great Britain or Ireland during his stud career, although the vast majority have done so. Northern Dancer is the most notable example of a North American-based stallion who won this title. The Northern Dancer sire line has dominated the list for the last several decades, mostly through his son Sadler's Wells (14 titles) and grandson Galileo (12 titles).^[1]

Most championships:^[2]

• 14 – Sadler's Wells – 1990, 1992–2004
• 13 – Highflyer – 1785–1796, 1798
• 12 – Galileo – 2008, 2010–2020
• 10 – Sir Peter Teazle – 1799–1802, 1804–1809
• 9 – St. Simon – 1890–1896, 1900–1901
• 8 – Regulus – 1754–1757, 1761, 1763, 1765–1766; Herod – 1777–1784

Excluding any championships by the foundation stallions themselves, the following sire-lines have produced champion sires (1721–2016):^[2][3]

• Darley Arabian – 88 stallions, 188 championships. all titles since 1964
• Byerley Turk – 17 stallions, 59 championships, most recently Tetratema in 1929
• Godolphin Arabian – 12 stallions, 32 championships, most recently Chamossaire in 1964
• D'Arcy White Turk – 3 stallions, 10 championships, most recently Bolton Starling in 1744
• Curwen's Bay Barb – 2 stallions, 4 championships, most recently Crab in 1750
• Acaster Turk, Bloody Buttocks, St. Victor's Barb, Thoulouse Barb – 1 championship each

• Leading sire in Australia
• Leading sire in France
• Leading sire in Germany
• Leading sire in Japan
• Leading sire in North America
• Leading broodmare sire in Great Britain & Ireland
• Leading broodmare sire in North America
• Leading jump racing sire in Great Britain & Ireland