Sydney Box (born April 29, 1907 in Beckenham, Kent, England, died 25 May 1983) was a British film producer and screenwriter, brother of another prominent British filmmaker, Betty Box. He produced the postwar screenplay, The Seventh Veil, which earned him the 1946 Oscar for best original screenplay with his then wife Muriel Box. He ended his cinema career in 1958 to concentrate on TV work.

Sydney and Muriel divorced in 1969.

He wrote many of his own screenplays as well as more than 50 one-act plays.

Brother of Betty E. Box