The 1959 Isle of Man TT, the second round of the 1959 Grand Prix motorcycle racing season, involved races on both the Mountain Course and the Clypse Course on the Isle of Man. John Surtees won the Senior race with a time of 3:00.13.4, adding to his earlier victory in the Junior race. Tarquinio Provini won both the Lightweight and Ultra-Lightweight categories, while Walter Schneider and H.Strauss won the sidecar event.