Sydney Valentine Nossiter (1865 – 23 December 1919), known professionally as Sydney Valentine, was an English actor of the Victorian and Edwardian eras. He was President of the Actors' Association and was remembered for negotiating what became the standard contracts for actors in the West End and on tour. He was born at Kings Norton, Birmingham, in 1865, when his birth was registered with the spelling "Sidney Valentine Nossiter".