Leif Mortensen (born 16 August 1940) is a Danish former professional footballer who played throughout Europe as a winger.
Born in Copenhagen, Mortensen began his career with hometown club KB. He spent a year in Italy with Udinese, making five league appearances, before returning to KB. He later spent two seasons in Scotland with Aberdeen, scoring one goal in fifteen league appearances.
Mortensen also made two appearances for the Danish under-21 side in 1961.