The Istanbul Marathon is an international athletics event organized by the metropolitan municipality in Istanbul, Turkey, every year on a Sunday in October since 1979.

The course is asphalt, mostly flat and is free of traffic. It is the only course in the world where the marathon includes two continents, Asia and Europe, in one race. The marathon starts on the Asian side of the city, short before the First Bosphorus Bridge, crosses the bridge giving an outstanding view of the Bosphorus and Istanbul, and passes many historic sites including the Blue Mosque and Hagia Sophia, and ends in the Inonu Stadium in the European part. In all, the race crosses three bridges, one over the Bosporus and two over the Golden Horn. The course changed three times over the years, therefore winning scores differ.