Sir William Frederick Neill was a Unionist MP and estate agent who served as Lord Mayor during 1947 and 1948.

Neill entered the Belfast Corporation in 1938 as a councillor for Duncairn and was elected as alderman the following year. In 1948, he was knighted and the following year was made a deputy lieutenant for Belfast. He also received the freedom of the city in 1949.

In 1945, Neill was elected as MP for North Belfast and served at Westminster for five years. He represented the Ulster Unionist party.

Neill was chairman of the Belfast Water Board and was made President of the British Waterworks Association in 1951. He also served on the Belfast Harbour Board and on the Senate of Queen’s University.

A keen sportsman, Neill and acted as president of the Golfing Union of Ireland and as president of Cliftonville Football Club.

Neill died aged seventy on 3 January 1960, on board the S.S. Pretoria Castle while sailing home from South Africa. He was buried at sea.