The 1999 Prix de l'Arc de Triomphe was a horse race held at Longchamp on Sunday 3 October 1999. It was the 78th running of the Prix de l'Arc de Triomphe.
The winner was Montjeu, a three-year-old colt trained in France by John Hammond. The winning jockey was Michael Kinane.
Further details of the winner, Montjeu.