Kossuth William Duncan (29 July 1857 – 30 June 1919) was a South Australian miller and politician.
He was a member of the South Australian Legislative Council for Northern District from 1900 to 1902 and a member of the South Australian House of Assembly for Stanley from 1907 to 1910.
[2] Around 1902 he moved to Laura, and for a number of years with Joseph King of Georgetown, as King & Duncan, ran the Laura flour mill.
[3] In 1911 he was elected, unopposed, to the Corporate Town of Laura, representing North Ward, and was Mayor in 1913-14.
He was an active member of the Church of Christ, and from 1914 a trustee of the State Bank.