Seppo Harjanne (born 20 February 1948) is a Finnish former rally co-driver. He is best known for co-driving for Timo Salonen from 1979 to 1988 and for Tommi Mäkinen from 1990 to 1997. With Salonen, Harjanne took ten World Rally Championship victories for the factory teams of Datsun, Peugeot and Mazda, and the 1985 drivers' world championship title in a Peugeot 205 Turbo 16 E2. With Mäkinen, competing mainly for the Team Mitsubishi Ralliart, he won ten more WRC events along with the 1996 and 1997 drivers' titles in a Lancer Evolution.