Macaron
- Macaron (horse) – 1874: Prix Morny
- Macaron (horse sired by Chateau Bouscaut) – 1941: Prix du Prince d'Orange
Macaroni
- Macaroni (horse) – b. 1860
- Macaroni (horse sired by Passebreul) – 1932–33: Grand Prix de Saint-Cloud, Prix du Conseil de Paris, Prix de Fontainebleau, Prix d'Hédouville etc.
- Macaroni (steeplechase horse) – 1885: Great Northern Steeplechase
Macdonald
- Macdonald (horse) – 1902–03: Deutsches Derby, Hansa-Preis
- Macdonald II – 1904–05: Fürstenberg-Rennen, Prix du Conseil de Paris, Prix Exbury, Prix Royal-Oak
Madagascar
- Madagascar (horse) – 1933: Queen Anne Stakes
- Madagascar (horse sired by St Damien) – 1897: Prix La Rochette
Madame du Barry
- Madame du Barry (horse) – 1878–81: Goodwood Cup, Irish Derby, November Handicap
- Madame du Barry (horse foaled in 1929) – 1931: Prix Isonomy
Madeline
- Madeline (horse) – 1843: Union-Rennen
- Madeline (horse sired by Sweeper) – 1927: Prix de Meautry
Magic
- Magic (horse) – b. 2006 (therapy horse)
- Magic (horse sired by Ascetic) – 1884: Anglesey Stakes
- Magic (horse sired by Martagon) – 1910: Goodwood Cup
Magic Night
- Magic Night (horse) – 1961: Golden Slipper Stakes
- Magic Night (horse) – 1990–92: Prix d'Aumale, Prix Foy, Prix de Malleret, Prix de Pomone, Prix Vermeille
Magister
- Magister (horse) – 1942: Grand Prix de Paris, Prix du Jockey Club
- Magister (horse sired by Fulmen) – 1898: Grosser Preis von Berlin
- Magister (horse sired by Le Hardy) – 1896: Prix Eclipse
Magnus
- Magnus (horse) – 1933: La Coupe de Maisons-Laffitte, Prix du Lys
- Magnus (horse sired by Flying Spur) – 2006–07 WTRR, 2007 WTRR, 2007–08 WTRR, 2008 WTR
Magpie
- Magpie (horse) – 1928–29: Leading sire in Australia
- Magpie (horse sired by Young Blacklock) – 1836: Anglesey Stakes
- Magpie (steeplechase horse) – 1886: List of Grand National first four placings
Magyar
Mahmoud
- Mahmoud (horse) – b. 1933
- Mahmoud (horse foaled c. 1880) – 1884: Prix Daniel Wildenstein
Mahogany
- Mahogany (horse) – b. 1990
- Mahogany (horse sired by Tap on Wood) – 1983–84: Fred Darling Stakes, Rockfel Stakes
Maid of Perth
- Maid of Perth – 1871–72: Nassau Stakes, Park Hill Stakes, Railway Stakes (Ireland), Yorkshire Oaks
- Maid of Perth (horse sired by Tetrameter) – 1928: Queen's Vase
Majestic
- Majestic (horse) – 1999: Hyde Novices' Hurdle
- Majestic (horse sired by William the Third) – 1913: Grosser Preis von Berlin, Union-Rennen
Major
- Major (horse) – 1954: Prix Greffulhe
- Major (horse sired by Lally) – 1925: Gran Premio del Jockey Club, St. Leger Italiano
Mameluke
- Mameluke (British horse) – b. 1824
- Mameluke (horse) – b. 1948
Mamounia
- Mamounia (horse) – 2002: Sceptre Stakes
- Mamounia (horse sired by Chanteur) – 1955: Acomb Stakes
Mandarin
- Mandarin (horse) – 1916: Breeders' Stakes, Queen's Plate
- Mandarin (horse) – 1957–62: Cheltenham Gold Cup, Grand Steeple-Chase de Paris, Hennessy Gold Cup, King George VI Chase etc.
- Mandarin (horse foaled c. 1901) – 1905: Prix du Gros Chêne
- Mandarin (horse sired by Aventin) – 1951: Hansa-Preis
- Mandarin (horse sired by Belshazzar) – 1839: Union-Rennen
Manfred
- Manfred (horse) – 1817: 2,000 Guineas Stakes
- Manfred (horse) – 1925–26: Caulfield Cup, Cox Plate
- Manfred (horse sired by Maintenon) – 1910: Prix La Rochette, Prix Morny
Manitoba
- Manitoba (horse) – b. 1930
- Manitoba (horse sired by Prudent) – 1969: Grand Prix de Vichy-Auvergne
Manitou
- Manitou (horse) – 1897: Prix Eclipse, Prix du Petit Couvert
- Manitou III – 1949–50: Prix Edmond Blanc
Marcantonio
- Marcantonio (horse) – 1952: Premio Parioli
- Marcantonio (horse sired by Melton) – 1900–01: Gran Premio di Milano, Premio Presidente della Repubblica
Marcellus
- Marcellus (horse) – 1823: Ascot Gold Cup
- Marcellus (horse sired by Pergolese) – 1924: Zukunfts-Rennen
Marcus
- Marcus (horse) – 1915: Coventry Stakes
- Marcus (horse sired by Dagor) – 1921–22: Premio Presidente della Repubblica, Premio Roma
Marengo
- Marengo (horse) – b. 1793 (warhorse)
- Marengo (horse sired by Monarque) – 1866: Prix Daru
- Marengo (horse sired by Premonition) – 1960: Sandown Classic Trial
- Marengo (racehorse) – 1844–47: 7th 1844 Grand National, Fell 1847 Grand National
Margrave
- Margrave (American horse) – 1896: Preakness Stakes
- Margrave (horse) – b. 1829
Marigold
- Marigold (horse) – 1864: Stewards' Cup (Great Britain)
- Marigold (horse sired by Miroir de Portugal) – 1902: Critérium de Saint-Cloud
Marjolet
- Marjolet (horse) – 1955: Prix d'Hédouville
- Marjolet (horse sired by Massine) – 1941: La Coupe
Mark
- Mark (horse) – 2004: Olympics – Individual dressage, Olympics – Team dressage
- Mark (horse sired by Rocket) – 1984: Bénazet-Rennen
- Mark (horse sired by Young Mogul) – 1771–72: Doncaster Cup
Mars
- Mars (horse) – 1926: Travers Stakes
- Mars (horse foaled c. 1875) – 1879: November Handicap
Marsyas
- Marsyas (horse) – b. 1940
- Marsyas (horse sired by Orlando) – 1853: July Stakes
Martial
- Martial (horse) – b. 1957
- Martial (horse sired by Airlie) – 1912: La Coupe de Maisons-Laffitte, Prix Exbury
Martini
- Martini (horse) – 1956: Futurity Stakes (Ireland)
- Martini (horse sired by Hermit) – 1882: Portland Handicap
Marvel
- Marvel (horse) – 1921: Prix Daniel Wildenstein, Prix de Pomone
- Marvel (horse sired by Marden) – 1890–92: Portland Handicap, Stewards' Cup (Great Britain)
Marwari
- Marwari (horse) – (redirects to Marwari horse) – horse breed
- Marwari (racehorse) – 1955: White Rose Stakes
Marylebone
- Marylebone (horse) – 2003: Matron Stakes (United States)
- Marylebone (horse sired by La Farina) – 1930: Prix de Pomone
Masetto
- Masetto (horse) – 1955–56: Bayerisches Zuchtrennen, Deutsches St. Leger, Grosser Preis von Baden, Grosser Preis von Berlin, Hansa-Preis etc.
- Masetto (horse foaled c. 1830) – 1834: Ayr Gold Cup
Masked Marvel
- Masked Marvel (horse) – b. 2008
- Masked Marvel (horse sired by Hard to Beat) – 1979: Newmarket Stakes
- Masked Marvel (horse sired by McKinley) – 1925: Cambridgeshire Handicap
Master Willie
- Master Willie – 1980–81: Coronation Cup, Easter Stakes, Eclipse Stakes, International Stakes, Jockey Club Stakes
- Master Willie – 1985: Yonkers Trot
- Master Willie (horse foaled in 1864) – 1866: Railway Stakes (Ireland)
Mata Hari
- Mata Hari (horse) – b. 1931
- Mata Hari (horse sired by Orsini) – 1972: Poule d'Essai des Pouliches
Mate
- Mate (horse) – b. 1928
- Mate (horse sired by Blandford) – 1885: Ebor Handicap
Matilda
- Matilda (horse) – b. 1824
- Matilda (horse sired by Solon) – 1878: Royal Whip Stakes
Matterhorn
- Matterhorn (horse) – 1912: Union-Rennen
- Matterhorn (horse sired by Wirbelwind) – 1958: Herzog von Ratibor-Rennen
Maureen
- Maureen (horse) – 2012–13: Fred Darling Stakes, Princess Margaret Stakes
- Maureen (horse sired by Son-in-Law) – 1933: Queen Mary Stakes
Maurice
- Maurice (horse) – 1896: Toronto Cup Stakes
- Maurice (horse sired by St Damien) – 1898–99: Prix des Chênes, Prix Noailles
Max
- Max (horse) – 2006: Ind. freestyle dressage at Equestrian Games, Ind. special dressage at Equestrian Games
- Max (racehorse) – 1888: Prix Berteux
Mazeppa
- Mazeppa (horse) – 1922–24: Prix Jean Prat, Prix du Lys, Prix Perth
- Mazeppa (horse sired by Wild Dayrell) – 1866: Craven Stakes
- Mazeppa (horse sired by Wolf's Crag) – 1899: Portland Handicap
Mazurka
- Mazurka (horse) – 1881: Coronation Stakes, Stewards' Cup (Great Britain)
- Mazurka (horse sired by Menetrier) – 1960: Arkle Challenge Trophy
Meda
Medaille d'Or
- Medaille d'Or – 1978: Coronation Futurity Stakes, Canadian Champion Two-Year-Old Colt
- Medaille d'Or (horse sired by Primo Dominie) – 1992: Sprint Stakes
Medina
- Medina (horse) – 2006: Individual endurance at the 2006 FEI World Equestrian Games
- Medina (racehorse) – 1957: Princess Margaret Stakes
Medium
- Medium (horse) – 1949–50: Grand Prix de Saint-Cloud, Prix du Prince d'Orange
- Medium (horse sired by Maskelyne) – 1893: La Coupe
Medoc
- Medoc (horse) – 1840–41: Leading sire in North America
- Medoc II – 1942: Cheltenham Gold Cup
- Medoc II – Bulgaria at the 2004 Summer Olympics, Equestrian at the 2004 Summer Olympics – Individual jumping
Medora
- Medora (horse) – b. 1811
- Medora (horse sired by Bend Or) – 1893: Stewards' Cup (Great Britain)
Mehari
- Mehari (horse) – 1908–09: Prix Hocquart, Prix Morny
- Mehari (horse sired by Lavandin) – 1966–67: Prix Kergorlay, Sagaro Stakes, Sandown Classic Trial
Melchior
- Melchior (horse) – 1893: Prix Eclipse, Zukunfts-Rennen
- Melchior (horse foaled c. 1953) – 1957: Zawawi Cup
Meleager
- Meleager (horse) – 1911: Wokingham Stakes
- Meleager (horse sired by Blackdrop) – 1860: Zukunfts-Rennen
Mellifont
- Mellifont (horse) – 1885: Anglesey Stakes
- Mellifont (horse sired by St Brendan) – 1913: Anglesey Stakes
Melodist
- Melodist – 1937: Wood Memorial Stakes
- Melodist (horse sired by The Minstrel) – 1988: Irish Oaks, Oaks d'Italia
Melody
- Melody (horse) – 1891: Prince of Wales's Stakes
- Melody (horse foaled in 1866) – 1868: Anglesey Stakes, Railway Stakes (Ireland)
Memento
- Memento (horse) – 1881: Flash Stakes
- Memento (horse sired by Roberto) – 1982: Ballycorus Stakes
Mephisto
- Mephisto (horse) – 2004–05: Ebor Handicap, Premier Kelso Hurdle, Prestige Novices' Hurdle
- Mephisto (horse sired by Robert the Devil) – 1886–90: Challenge Stakes, Golden Jubilee Stakes, Jersey Stakes, July Cup
Mercurius
- Mercurius (horse) – 1963–65: Grosser Preis von Berlin, Grosser Preis der Landeshauptstadt Düsseldorf, Mehl-Mülhens-Rennen, Rheinland-Pokal
- Mercurius (horse foaled c. 1951) – 1955–56: Zawawi Cup
Mercutio
Meridian
- Meridian (horse) – b. 1908
- Meridian (horse sired by Glaucus) – 1848: Union-Rennen
Merigo
- Merigo – 2009: Eider Chase
- Merigo (horse foaled in 1936) – 1943: Prix de Barbeville
Merlin
- Merlin (horse) – 1895–96: Grand Prix de Deauville, Prix Eugène Adam, Prix Exbury, Prix de Guiche, Prix de Lutèce
- Merlin (steeplechase horse) – 1874: List of Grand National first four placings
Mermaid
Merry Court
- Merry Court – 1968: Byrne Group Plate
- Merry Court (horse foaled in 1945) – 1951: Johnny Henderson Grand Annual Chase
Merryman
- Merryman (horse) – 1858: Molecomb Stakes
- Merryman II – 1959–61: List of Grand National winners, List of Grand National first four placings, Scottish Grand National
Mersey
- Mersey (horse) – 1985–86: Prix Foy, Prix de Royallieu, Prix Royal-Oak, 8th 1986 Prix de l'Arc de Triomphe
- Mersey (horse sired by Knowsley) – dam of Carbine
Meteor
- Meteor (horse) – b. 1839
- Meteor (horse sired by Ariel) – 1928: Gerling-Preis
- Meteor (show jumping horse) – 1956: Show Jumping World Championships
Meteora
- Meteora (horse) – b. 1802
- Meteora (horse sired by Melbourne) – 1854: Jersey Stakes
Michelangelo
- Michelangelo (horse) – 1921: Derby Italiano, Gran Premio d'Italia, St. Leger Italiano
- Michelangelo (horse sired by Galileo) – 2012: Cocked Hat Stakes
Midas
- Midas (horse) – 1851: Newmarket Stakes
- Midas (horse sired by Hyperion) – 1945: Newmarket Stakes
Midshipman
- Midshipman (horse) – b. 2006
- Midshipman (horse sired by Hauban) – 1978: Prix Maurice de Nieuil, Prix Vicomtesse Vigier
Miel Rosa
- Miel Rosa – 1950: La Coupe
- Miel Rosa (horse sired by Saint Just) – 1927: Prix Yacowlef
Mignonette
- Mignonette (horse) – 1873: Queen's Plate
- Mignonette (horse sired by Vertugadin) – 1874: Prix Royal-Oak
Milan
- Milan (horse) – b. 1998
- Milan (horse sired by Migoli) – b. 1954
- Milan (horse sired by Le Sarrazin) – 1881: Prix du Cadran
Milesius
- Milesius (horse) – 1988–89: Manhattan Handicap
- Milesius (horse sired by Milesian) – 1966: Ayr Gold Cup
- Milesius (horse sired by Roi Herode) – 1920: Coventry Stakes
Milford
- Milford (horse) – 1979: Lingfield Derby Trial, Princess of Wales's Stakes, White Rose Stakes
- Milford (horse sired by Saraband) – 1892: Coventry Stakes, July Stakes
Milton
- Milton (horse) – b. 1977 (show jumping)
- Milton (horse sired by Bay Middleton) – 1855: Norfolk Stakes (Great Britain)
- Milton (horse sired by Marcovil) – 1919: Ribblesdale Stakes
Miner's Lamp
- Miner's Lamp – 1958: Investec Derby Trial, Princess of Wales's Stakes
- Miner's Lamp (horse sired by High Top) – 1980: Oettingen-Rennen
Minos
- Minos (horse) – 1856: List of Grand National first four placings
- Minos (horse sired by Justice) – 1792: Craven Stakes
Minstrel
- Minstrel (horse) – 1897–98: King Edward VII Stakes, Wokingham Stakes
- Minstrel (horse sired by Tudor Minstrel) – 1954: Cambridgeshire Handicap
Mirabilis
- Mirabilis (horse) – 2006: Churchill Distaff Turf Mile Stakes
- Mirabilis (horse sired by Teddy) – 1928: Prix Yacowlef
Miracle
- Miracle (horse) – 1931–32: Eclipse Stakes, Gimcrack Stakes, Newmarket Stakes
- Miracle (horse sired by High Hat) – 1969: Solario Stakes
- Miracle (horse sired by Soothsayer) – 1818: July Stakes
Modena
- Modena (horse) – 1888: Prix de Royaumont
- Modena (horse sired by Parmesan) – 1874: Stewards' Cup (Great Britain)
Mojave
- Mojave (horse) – 1992: Hungerford Stakes
- Mojave (horse sired by Dubawi) – 2011: Zetland Stakes
Momentum
Momus
- Momus (horse) – 1955: Toronto Cup Stakes
- Momus (horse sired by Ramrod) – 1925: Grand Prix de Vichy-Auvergne
Mon Tresor
- Mon Tresor – 1988: Middle Park Stakes, Zukunfts-Rennen
- Mon Tresor (horse sired by Gainsborough) – 1939: Prix Daru, Prix de Fontainebleau
Monaco
- Monaco (horse) – 2004–08: 2004 Olympics – Individual jumping, 2004 Olympics – Team jumping, 2008 Olympics – Individual jumping
- Monaco (racehorse) – 1876: Stewards' Cup (Great Britain)
Monarque
- Monarque – 1855–57: Goodwood Cup, Poule d'Essai des Poulains, Prix du Cadran, Prix Daru, Prix Gladiateur, Prix du Jockey Club
- Monarque II – 1887: Prix du Jockey Club
Monitor
- Monitor (horse) – 1879–83: Champion Stakes (United States), Dixie Stakes, Grand National Handicap, Monmouth Cup (1870)
- Monitor (horse sired by Codoman) – 1908: Poule d'Essai des Poulains, Prix Omnium II
- Monitor (horse sired by Gunboat) – 1865: Railway Stakes (Ireland)
Monrovia
- Monrovia (horse) – 1893: Kentucky Oaks
- Monrovia (horse sired by Pharis) – 1951: Prix de Royallieu, Prix de Royaumont
Monseigneur
- Monseigneur (horse) – 1977–78: Prix du Conseil de Paris, Prix d'Harcourt
- Monseigneur (horse sired by Orphelin) – 1869–71: Grosser Preis von Baden, Prix de la Forêt
- Monseigneur (horse sired by Straight Deal) – 1949: Railway Stakes (Ireland)
Montevideo
- Montevideo (horse) – b. 1971 (dressage)
- Montevideo (horse sired by Honeyway) – 1968–69: Premio Carlo Vittadini, Prix Daniel Wildenstein
- Montevideo (horse sired by Tresor) – 1949: Bayerisches Zuchtrennen
Montreal
- Montreal (horse) – 2004: Olympics – Individual jumping, Olympics – Team jumping
- Montreal (horse foaled in 1927) – 1930: Prix Omnium II
- Montreal (horse sired by Chamberlin) – 2000–04: Prestbury Juvenile Novices' Hurdle, 2004 Grand National (fell)
- Montreal (horse sired by Langar) – 1839: Newmarket Stakes
Montrose
- Montrose (horse) – b. 1884
- Montrose (horse sired by Coronach) – 1936: Duke of York Handicap
- Montrose II – 1911: Critérium de Maisons-Laffitte, Prix de la Forêt, Prix Jean-Luc Lagardère, Prix Robert Papin, Prix de Seine-et-Oise
Moon Over Miami
- Moon Over Miami (horse) – 2006–07: Sharp Novices' Hurdle, November Novices' Chase
- Moon Over Miami (horse sired by Beveled) – 1993: Oak Tree Stakes
Moonlight Dance
- Moonlight Dance – 1994: Prix Saint-Alary
- Moonlight Dance (horse sired by Sinndar) – 2005: International Stakes (Ireland)
Morse Code
- Morse Code (horse) – 1938: Cheltenham Gold Cup
- Morse Code (horse sired by Morston) – 1979: November Handicap
Moscow Ballet
- Moscow Ballet (horse) – 2004: Tercentenary Stakes
- Moscow Ballet (horse sired by Nijinsky) – 1984: Railway Stakes (Ireland)
Moss Rose
- Moss Rose (horse) – 1879: Queen's Plate
- Moss Rose (horse sired by Blacklock) – 1830: Dee Stakes
Moss Trooper
- Moss Trooper – 1843: Northumberland Plate
- Moss Trooper (horse sired by Levmoss) – 1975: Prix Kergorlay
Mother Goose
- Mother Goose (horse) – 1924: American Champion Two-Year-Old Filly, Belmont Futurity Stakes, Fashion Stakes
- Mother Goose (horse sired by Escamillo) – 1958: Princess Royal Stakes
Mother of Pearl
- Mother of Pearl (horse) – 1998: Prix Saint-Roman
- Mother of Pearl (horse sired by Knight of Kars) – 1866: Coronation Stakes
Motivator
- Motivator (horse) – b. 2002
- Motivator (horse sired by General Ironside) – 1986: Pertemps Final
Mount Athos
- Mount Athos (horse) – 2012: Geoffrey Freer Stakes
- Mount Athos (horse sired by Sunny Way) – 1968: Gordon Stakes, Princess of Wales's Stakes
Mourad
- Mourad (horse) – 2010–12: Boyne Hurdle, Christmas Hurdle (Ireland), Galmoy Hurdle
- Mourad (horse sired by Maintenon) – 1927: Critérium de Maisons-Laffitte, Prix de Seine-et-Oise
Mozart
- Mozart (eventing horse) – 2004: Equestrian at the 2004 Summer Olympics – Team eventing
- Mozart (horse) – b. 1998
- Mozart (horse sired by Figaro) – 1837: Union-Rennen
Mr John
- Mr John – 2002: Cornhusker Handicap
- Mr John (horse sired by Northfields) – 1986: Amethyst Stakes, 9th 1986 Epsom Derby
Muscovite
- Muscovite (horse) – 1980: Ballycorus Stakes, International Stakes (Ireland)
- Muscovite (horse sired by Hetman Platoff) – 1854: Cesarewitch Handicap
Musician
- Musician (horse) – 1850: King Edward VII Stakes
- Musician (horse sired by Worthy) – 1807: Newmarket Stakes
My Dear
- My Dear II – 1917–18: Champion Stakes, Dewhurst Stakes, Epsom Oaks
- My Dear III – b. 1917
Myosotis
- Myosotis (horse) – 1933: Lingfield Derby Trial
- Myosotis (horse sired by Mr. Leader) – 1974: Prix du Bois
Mystery
- Mystery (horse) – 1961: National Stakes
- Mystery IX – 1951: Eclipse Stakes
Mystic
- Mystic (horse) – 1984–85: Hong Kong Horse of the Year
- Mystic (horse sired by Hedley) – 1822: Newmarket Stakes
- Mystic II – 1957: Prix de Seine-et-Oise
Nadia
Nadir
- Nadir (horse) – b. 1955
- Nadir (horse foaled in 1928) – 1931: Prix de Guiche
Nancy
- Nancy (horse) – 1880: Monmouth Oaks
- Nancy (horse sired by Master Wags) – 1854: Poule d'Essai des Poulains
- Nancy (horse sired by Pompey) – 1851: Chester Cup, Ebor Handicap, Goodwood Cup
Napoleon
- Napoleon (horse) – 2008: Yonkers Trot
- Napoleon (horse sired by Bob Booty) – 1829–33: Royal Whip Stakes
- Napoleon (horse sired by Galopin) – 1889: Golden Jubilee Stakes
- Napoleon (horse sired by Pilliwinkie) – 1931: Goldene Peitsche
- Napoleon III (horse) – 1873: Champagne Stakes (Great Britain)
- Napoleon III (horse sired by Iago) – 1856: Craven Stakes
Napper Tandy
- Napper Tandy (horse) – 2003: Diamond Stakes
- Napper Tandy (steeplechase horse) – 1905: List of Grand National first four placings
Nashua
- Nashua (horse) – b. 1952
- Nashua (filly) – 1952: Irish 1,000 Guineas, Pretty Polly Stakes (Ireland)
Nat
- Nat (horse) – 1856–57: Poule d'Essai des Poulains, Prix du Cadran, Prix Daru
- Nat (horse sired by Jereed) – 1843: Cambridgeshire Handicap
Nativa
- Nativa (horse) – 1843–44: Prix du Cadran, Prix de Diane
- Nativa (horse sired by Saxifrage) – 1890: Prix Kergorlay
Necklace
- Necklace (horse) – 2003: Debutante Stakes (Ireland), Moyglare Stud Stakes
- Necklace (horse sired by Lemberg) – 1928: Prix La Rochette, Prix Morny, Prix Robert Papin
Nectar
- Nectar (horse) – 1816: 2,000 Guineas Stakes
- Nectar (horse sired by Hobneck) – 1937: Northumberland Plate
Nectarine
- Nectarine (horse) – 1910: Critérium de Maisons-Laffitte, Prix de la Salamandre
- Nectarine (horse sired by Nearco) – 1953: Lingfield Oaks Trial
Nero
- Nero (horse) – 1975: Cane Pace
- Nero (horse foaled c. 1902) – 1906: Portland Handicap
- Nero (horse sired by Don Carlos) – 1886: Grosser Preis von Baden
Net
- Net (horse) – 1921: Prix Daphnis
- Net (horse sired by Clarion) – 1961: Prix Jacques Le Marois
Nettuno
- Nettuno (horse) – 1913: Derby Italiano, Premio Parioli
- Nettuno (horse sired by Ticino) – 1959: Oettingen-Rennen
Newminster
- Newminster (horse) – 1851–63: St. Leger Stakes, Leading sire in Great Britain and Ireland
- Newminster (horse sired by The Marquis) – 1879–97: Caulfield Cup, Leading sire in Australia
Night Shift
- Night Shift (horse) – b. 1980, see Azamour, Daryakana
- Night Shift (horse sired by Trimdon) – 1939: Yorkshire Oaks
Nike
- Nike (horse) – b. 1794
- Nike (show jumping horse) – 2004–06: Olympics – Individual jumping, Olympics – Team jumping, Eq. Games – Individual jumping, Eq. Games – Team jumping
Nil
Nimbus
- Nimbus (FR) – b. 1910
- Nimbus (GB) – b. 1946
No Mercy
- No Mercy (horse) – 2000–08: 2000 Olympics ind. jumping, 2004 Olympics ind. jumping, 2004 Olympics team jumping, 2008 Olympics ind. jumping
- No Mercy (racehorse) – 1971: European Free Handicap, Prix de Meautry
Noble Chieftain
- Noble Chieftain – 1888: King's Stand Stakes
- Noble Chieftain (horse sired by Nearco) – 1954: Coventry Stakes
Nonancourt
- Nonancourt (horse) – 1877: Prix Chaudenay
- Nonancourt (horse sired by Val de Loir) – 1969: Prix Chaudenay
Norfolk
- Norfolk (horse) – b. 1861, see El Rio Rey, Emperor of Norfolk, Glencoe I, Yo Tambien etc.
- Norfolk (horse sired by Masetto) – 1967–70: G. P. von Berlin, G. P. der Landeshauptstadt Düsseldorf, Preis der Sparkassen-Finanzgruppe
Norman
- Norman (horse) – 1908: 2,000 Guineas Stakes
- Norman (horse foaled c. 1950) – 1954: Zawawi Cup
- Norman (horse sired by Norseman) – 1952–55: Gran Premio del Jockey Club, Prix du Chemin de Fer du Nord, Prix Foy
- Norman horse – horse breed, see Boulonnais horse, Canadian horse, Comtois horse
Northern Light
- Northern Light (horse) – 1953: Grand Prix de Paris, Prix Juigné
- Northern Light (horse sired by Chanticleer) – 1860: Dee Stakes
Novice
- Novice (horse) – 1879–80: Ebor Handicap, Seaton Delaval Stakes
- Novice (racehorse) – National Hunt racehorse classification
Obeah
- Obeah (horse) – b. 1965
- Obeah (horse sired by Cure the Blues) – 1987: Prestige Stakes
Oberon
- Oberon (horse) – 1887: Lincoln Handicap
- Oberon (horse sired by Highflyer) – 1793: Doncaster Cup
- Oberon (horse sired by Orpheus) – 1931: Derby Italiano
Ocos
Octave
- Octave (horse) – b. 2004
- Octave (horse foaled c. 1878) – 1882: Prix du Prince d'Orange
- Octave (horse foaled c. 1879) – 1883: Prix du Gros Chêne
Ode
- Ode (horse) – 1953: Bing Crosby Handicap
- Ode (horse sired by Lord Avie) – 1990: Grand Prix de Chantilly, Prix Corrida
Olaf
- Olaf (horse) – 2008: 2008 CSIO Spruce Meadows 'Masters' Tournament – CN International
- Olaf (racehorse) – 1906: Goldene Peitsche
Old Bill
- Old Bill (horse) – 1976: Chester Vase
- Old Bill (horse sired by William the Third) – 1919: King Edward VII Stakes
Old England
- Old England (horse) – 1902: Preakness Stakes
- Old England (horse sired by Mulatto) – 1844: July Stakes, Norfolk Stakes (Great Britain)
Olden Times
- Olden Times – b. 1958
- Olden Times (horse sired by Darshaan) – 2001–03: Earl of Sefton Stakes, Feilden Stakes, Prix Jean Prat
Oleander
- Oleander (horse) – 1927–44: Grosser Preis von Baden, Grosser Preis von Berlin, Leading sire in Germany
- Oleander (horse sired by Isonomy) – 1895: Dee Stakes
Olympia
- Olympia (horse) – b. 1946
- Olympia (horse sired by Fortina) – 1960: Irish Grand National
Olympian
- Olympian (horse) – 2000–01: Kennedy Road Stakes, Play The King Stakes
- Olympian (horse sired by High Line) – 1993: Coral Cup, Imperial Cup
Ontario
- Ontario (horse) – 2002: Anglesey Stakes
- Ontario (horse foaled c. 1878) – 1882: Prix du Petit Couvert
Opium
- Opium (horse) – 2008: Equestrian at the 2008 Summer Olympics – Individual jumping
- Opium (racehorse) – 1981–82: German 1,000 Guineas, Preis der Winterkönigin
Optimist
- Optimist (horse) – 1947: Åby Stora Pris
- Optimist (horse sired by Fervor) – 1919: Goldene Peitsche
- Optimist (horse sired by Tracy le Val) – 1923–24: Prix Daphnis, Prix de la Salamandre
Or du Rhin
- Or du Rhin – 1910: Prix Daru, Prix du Jockey Club
- Or du Rhin (horse sired by Prince Bio) – 1960–61: Prix Maurice de Nieuil
Orfeo
- Orfeo (horse) – Individual endurance at the 2006 FEI World Equestrian Games
- Orfeo (racehorse) – 1952: Grand Prix de Paris, Prix du Lys
Orient
- Orient (horse) – 1955: Show Jumping World Championships
- Orient (horse sired by Bona Vista) – 1910: Deutsches Derby, Hansa-Preis
- Orient (horse sired by Scottish Chief) – 1881: Union-Rennen
Orpen
- Orpen – 1931–33: Hardwicke Stakes, Yorkshire Cup
- Orpen (horse sired by Lure) – 1998: Prix Morny
Orpheus
- Orpheus (horse) – 1919–21: Champion Stakes, Duke of York Handicap, Norfolk Stakes (Great Britain), Princess of Wales's Stakes
- Orpheus (horse sired by The Minstrel) – 1989: Northumberland Plate
Orthodox
- Orthodox (horse) – 2009: American Turf Stakes
- Orthodox (horse sired by Hyperion) – 1941: Newmarket Stakes, St. James's Palace Stakes
Orvieto
- Orvieto (horse) – 1890–91: Norfolk Stakes (Great Britain), Sussex Stakes
- Orvieto (horse sired by Macherio) – 1953: Gran Criterium
Orwell
- Orwell (horse) – b. 1929
- Orwell (horse sired by Matchmaker) – 1906: Seaton Delaval Stakes
Oscar
- Oscar (horse) – b. 1994, see Coolmore Stud, Rock On Ruby, Synchronised (horse)
- Oscar (horse sired by Saltram) – 1800: Craven Stakes
- Oscar (steeplechase horse) – 1853: List of Grand National first four placings
Ossian
- Ossian (horse) – 1883: St. Leger Stakes, Sussex Stakes
- Ossian (horse sired by Fels) – 1921: Deutsches St. Leger, Grosser Preis von Baden, Grosser Preis von Berlin
- Ossian (horse sired by Le Sagittaire) – 1908–11: Grand Prix de Saint-Cloud, Prix du Conseil de Paris, Prix Eclipse, Prix Ganay, Prix d'Ispahan
Oviedo
- Oviedo (horse) – 1886–87: Prix de Condé, Prix du Gros Chêne
- Oviedo (horse foaled c. 1943) – 1947: Prix du Prince d'Orange
Pacific
- Pacific (horse) – 1926: Prix Daniel Wildenstein, Prix de Meautry
- Pacific (horse sired by Atlantic) – 1880: Prix Noailles
Paganini
- Paganini (horse) – 2006: Individual freestyle dressage at World Equestrian Games, Individual special dressage at World Equestrian Games
- Paganini (racehorse) – 1870: Ebor Handicap
Palais Royal
- Palais Royal (horse) – 1928–30: Cambridgeshire Handicap, Prix Hocquart, Prix Paul de Moussac
- Palais Royal (horse sired by Blücher) – 1822: July Stakes
Palladio
- Palladio (horse) – 2004: Equestrian at the 2004 Summer Olympics – Individual dressage, Switzerland at the 2004 Summer Olympics
- Palladio (horse) – 2005–09: Autumn Stakes (Canada), Eclipse Stakes (Canada), Ontario Derby, Seagram Cup Stakes etc.
- Palladio (horse sired by Albert Victor) – 1885: Newmarket Stakes
Pan
- Pan (horse) – b. 1805
- Pan (horse sired by Atys) – 1950–51: Ascot Gold Cup, Goodwood Cup, Prix Chaudenay, Prix Royal-Oak
- Pan (horse sired by Drumhead) – 1966: Stockholm Cup International
- Pan (steeplechase horse) – 1890: List of Grand National first four placings
Pandour
- Pandour – 1958: Dee Stakes
- Pandour (horse sired by Monarque) – 1869: Prix Hocquart
Panga
- Panga (horse) – 1995: Silver Flash Stakes
- Panga (horse sired by My Babu) – 1959: Cherry Hinton Stakes
Pantaloon
- Pantaloon (horse) – 1805: July Stakes
- Pantaloon (horse sired by Matchem) – 1771: Craven Stakes
Papillon
- Papillon (horse) – b. 1991
- Papillon (horse sired by Gladiator) – 1854: Prix du Cadran
Papua
- Papua (horse) – 2003–05: Hollie Hughes Handicap
- Papua (horse sired by Green Dancer) – 1997: 13th 1997 Epsom Derby
Paragon
- Paragon (horse) – 1786: St. Leger Stakes
- Paragon (horse sired by Radium) – 1921: Duke of York Handicap
Parasol
- Parasol (horse) – b. 1800
- Parasol (horse sired by Halling) – 2003: Huxley Stakes, Winter Derby
- Parasol (horse sired by Rueil) – 1897: Prix Chaudenay
- Parasol II – 1952: Christie's Foxhunter Chase
Pareo
- Pareo (horse) – 1951–52: Princess Margaret Stakes, Prix Chloe, Prix du Petit Couvert
- Pareo (horse sired by Armos) – 1979–80: Gran Criterium, Gran Premio d'Italia
Park Romeo
- Park Romeo – 1976: Nearctic Stakes
- Park Romeo (horse sired by Irish Love) – 1981: Bénazet-Rennen, Flieger Trophy, Prix du Petit Couvert
Parthenon
- Parthenon (horse) – 2009: Glasgow Stakes
- Parthenon (horse sired by Acropolis) – 1970: Goodwood Cup, Queen Alexandra Stakes
Pas de Deux
- Pas de Deux (horse) – 1978: Prix du Palais-Royal
- Pas de Deux (horse foaled in 1953) – 1955: Critérium de Saint-Cloud
Passaro
- Passaro (horse) – 1901–03: Prix de Barbeville, Prix Greffulhe
- Passaro (horse sired by Kircubbin) – 1929: Prix Chaudenay
Patch
- Patch (horse) – 1950: Del Mar Futurity
- Patch (horse sired by St. Paddy) – 1975: Great Voltigeur Stakes, Lingfield Derby Trial
Patience
- Patience (horse) – 1876: Monmouth Oaks
- Patience (horse) – 1905: Deutsches Derby, List of leading Thoroughbred racehorses
Patrizier
- Patrizier (horse) – 1944: Gerling-Preis, Grosser Preis der Landeshauptstadt Düsseldorf
- Patrizier (horse sired by Ard Patrick) – 1923: Herzog von Ratibor-Rennen
Patron
- Patron (horse) – 1829: 2,000 Guineas Stakes, Newmarket Stakes
- Patron (horse) – 1892: Belmont Stakes, Dwyer Stakes
- Patron (horse) – 1894: List of Melbourne Cup winners
Paul Jones
- Paul Jones (horse) – b. 1917
- Paul Jones (horse sired by Buccaneer) – 1868: Chester Cup
- Paul Jones (horse sired by Mossborough) – 1958: November Handicap
Paulina
- Paulina (horse) – b. 1804
- Paulina (steeplechase horse) – 1839: List of Grand National first four placings
Pavillon
- Pavillon (horse) – 2001: Red Bank Stakes
- Pavillon (horse sired by Verwood) – 1922: Prix Robert Papin
- Pavillon (steeplechase horse) – 1965: Prix Ferdinand Dufaure
Pavot
- Pavot – b. 1942
- Pavot (horse sired by Vimy) – 1962: Queen's Vase
Peace
- Peace (horse) – 1879: Park Hill Stakes
- Peace (horse sired by Xenophon) – 1882–83: Railway Stakes (Ireland), Royal Whip Stakes
Pearl Diver
- Pearl Diver – b. 1944
- Pearl Diver (steeplechase horse) – 1868–71: List of Grand National first four placings
Peeress
- Peeress (horse) – 2005–06: Lockinge Stakes, Sun Chariot Stakes, Windsor Forest Stakes, 2006 WTRR
- Peeress (horse sired by Newminster) – 1865: Nassau Stakes
Peppercorn
- Peppercorn (horse) – 1999–2004: Grosse Europa-Meile, Grosser Preis der Landeshauptstadt Düsseldorf, Herzog von Ratibor-Rennen
- Peppercorn (horse sired by Peppermint) – 1892: Gimcrack Stakes
Perion
- Perion (horse) – 1920–32: Ribblesdale Stakes, Leading sire in Japan
- Perion (horse sired by Northfields) – 1987–88: Bengough Stakes, Palace House Stakes, Sprint Stakes
Perla
- Perla (horse) – 1873–74: Grand Prix de Deauville, Prix Morny, Prix de la Salamandre
- Perla (horse sired by Young Emperor) – 1977: Curragh Stakes, Phoenix Stakes
Permit
Perouse
- Perouse (horse) – 2004: Elite Hurdle
- Perouse (horse sired by Gamin) – 1896: Prix Vanteaux
Persepolis
- Persepolis (horse) – 1981–82: Prix Lupin, Prix Noailles, Prix La Rochette
- Persepolis (horse sired by Caracalla) – 1959: Prix de Royallieu
Persian Majesty
- Persian Majesty – 1971: Supreme Novices' Hurdle
- Persian Majesty (horse sired by Grand Lodge) – 2003: Tercentenary Stakes
Peter
- Peter (horse) – 1878–81: Hardwicke Stakes, Middle Park Stakes, Royal Hunt Cup, Stewards' Cup (Great Britain)
- Peter (horse sired by Chamant) – 1891: Deutsches Derby, Mehl-Mülhens-Rennen
Peter Flower
- Peter Flower – 1950: Champion Stakes, Hardwicke Stakes
- Peter Flower (horse sired by Petrarch) – 1891–92: Golden Jubilee Stakes, Jersey Stakes
Peter Simple
- Peter Simple (horse) – b. 1838
- Peter Simple (horse sired by Arbutus) – 1841–45: List of Grand National first four placings
- Peter Simple (horse sired by Velocipede) – 1835: Dee Stakes
Peterhof
- Peterhof (horse) – 1976: Triumph Hurdle
- Peterhof (horse sired by The Minstrel) – 1981: Curragh Stakes, Flying Childers Stakes
Peut Etre
- Peut Etre – 1935: Prix de Fontainebleau
- Peut-etre (horse) – 1874: Cambridgeshire Handicap
Phaeton
- Phaeton (horse) – 1966–67: Grand Prix de Paris, Prix de Condé
- Phaeton (horse) – b. 1865, see Fonso, Leonatus
- Phaeton (horse foaled in 1851) – 1854: King Edward VII Stakes
Phaleron
- Phaleron (horse) – 1909: Jockey Club Stakes
- Phaleron (horse sired by Babu's Pet) – 1962: Prix Daniel Wildenstein
Phantom
- Phantom (horse) – b. 1808
- Phantom (horse sired by The Flying Dutchman) – 1859: Newmarket Stakes
Pharamond
- Pharamond (horse) – no links
- Pharamond II – b. 1925
- Pharamond (horse sired by Cidre Mousseux) – 1953: Grand Steeple-Chase de Paris
- Pharamond (horse sired by Sicambre) – 1959–60: Prix Daru, Prix Morny
Phenix
- Phenix (horse) – 1878–79: July Cup, Prix de la Forêt
- Phenix (horse foaled c. 1855) – 1859: Prix du Gros Chêne
Philanderer
- Philanderer (horse) – 1965: Brigadier Gerard Stakes
- Philanderer (horse sired by Prince Philip) – 1926: Royal Whip Stakes
Philemon
- Philemon (horse) – 1962: Anglesey Stakes
- Philemon (horse foaled c. 1924) – 1928: Prix du Pin
Phlegethon
- Phlegethon (horse) – 1889: Poule d'Essai des Poulains, Prix de Guiche
- Phlegethon (horse foaled in 1848) – 1851: King Edward VII Stakes
Phocion
- Phocion (horse) – 1893: King Edward VII Stakes, St. James's Palace Stakes
- Phocion (horse sired by Sampson) – 1778: Doncaster Cup