William Parkin (24 August 1801 – 31 May 1889) was a businessman politician and philanthropist in the early days of the Colony of South Australia
Parkin was a native of Glastonbury, near Barnstaple, and emigrated to South Australia on the Recovery, arriving in September 1839. He operated a drapery on Hindley Street (later the site of Miller Anderson's) then Rundle Street, next to the Globe Hotel, (later J. Marshall & Co.'s emporium) with G. W. Chinner (died June 1880), at one time mayor of Brighton. The shop was later operated by his nephew John William Parkin (c. 1844 – 19 August 1882). (There are parallels with fellow-parliamentarian John Hodgkiss.) He left the trade and took a seat on the board of the Kadina and Wallaroo Railway Company, and was part owner of The Advertiser.
He represented City of Adelaide in the Legislative Assembly from March 1860 to 1862 and won a seat in the Legislative Council in 1866 and retired February 1877.
He was a member of the Freeman Street Congregationalist church then Glenelg, where the pastor was the Rev. C. Manthorpe.
He was a member of the committee under Rev. C. W. Evan, set up to erect the Stow Memorial Church, named for T. Q. Stow. Others were Richard Hanson, Thomas Graves, John Brown, John Davis, Horace Dean, Robert Davenport, Thomas Barlow, William Berry, Samuel Davenport, William Hanson, Henry Giles, Matthew Goode, Carrington Smedley, Clement Sabine, Robert Stuckey, Charles Todd, George White, Alexander Hay.