The Irish St. Leger is a Group 1flathorse race in Ireland which is open to thoroughbreds aged three years or older. It is run at the Curragh over a distance of 1 mile and 6 furlongs (2,816 metres), and it is scheduled to take place each year in September.
The event was established in 1915, and it was originally restricted to three-year-old horses only. It was modelled on the St. Leger Stakes in England, and the first horse to win both races was Royal Lancer in 1922. The first winner of the Irish Triple Crown (which comprises the Irish 2,000 Guineas, the Irish Derby and the Irish St. Leger) was Museum in 1935.
The Irish St. Leger was opened to horses aged four or older in 1983. Since then there have been several repeat winners, and the most successful is Vinnie Roe, who recorded his fourth victory in 2004. The leading horses from the race in recent years have often gone on to compete in the Melbourne Cup.