William Cooper (24 October 1909 – 18 May 1994) was a professional footballer who played as a full back for Aberdeen, his only club at the professional level.

Cooper played junior football with Mugiemoss before starting his professional career with Aberdeen in 1927. He played almost 400 official games for the club in a 20-year career which was temporarily halted by the Second World War in 1939 (he also made over 180 appearances in the unofficial regional competitions held during the conflict, several of which were won by the Dons, culminating in the nationwide 1946 Southern League Cup Final which his team won before a crowd of 135,000 at Hampden Park). After regular competitions resumed, Cooper played a large part in Aberdeen's 1946–47 Scottish Cup run but missed the final through injury; the Scottish Football Association gave Aberdeen permission to award him a winners' medal, despite him not playing on the day.^[2] He had also collected runners-up medals from the Scottish Cup in 1937, and the Scottish League Cup in 1947.

He represented the Scottish League XI twice, before the war.^[3]

Aberdeen

• Scottish Cup: 1947
  • Runner-up: 1937