The 1908 Isle of Man Tourist Trophy motorcycle races took place on the Short Course (St John's, Ballacraine, Kirk Michael. Peel, St John's).
22 September 1908 – 10 laps (158 ⅛ miles) St John's Short Course.
22 September 1908 – 10 laps (158 ⅛ miles) St John's Short Course.