Montjeu was an Irish-bred, French-trained thoroughbred horse racing racehorse and sire. In a racing career which lasted from September 1998 to November 2000, he ran sixteen times and won eleven races, including six at Group 1. After winning twice as a juvenile, he was the outstanding European racehorse of 1999, winning the Prix du Jockey Club, the Irish Derby and the Prix de l'Arc de Triomphe. Four more victories in 2000 included the King George VI and Queen Elizabeth Stakes. He was then retired to stud where he proved to be an outstanding sire of winners.

The Prix du Jockey Club, sometimes referred to as the French Derby, is a Group 1 flat horse race in France open to three-year-old thoroughbred colts and fillies. It is run at Chantilly over a distance of 2,100 metres each year in early June.