William J. S. Donnelly (c. 1844 – March 11, 1914) was an author and political figure in Newfoundland.
He represented Placentia and St. Mary's in the Newfoundland and Labrador House of Assembly from 1878 to 1889, from 1893 to 1894 and from 1897 to 1899 as a Liberal, then Reform and later as a Conservative.
[1] When Donnelly was named to cabinet in 1894, he was required to run for reelection in a by-election and was defeated by Liberal John T. Dunphy.
He was named to cabinet again in 1899, again was required to run for reelection and again was defeated, this time by Richard T.
He wrote A History of the Public Debt in Newfoundland 1834-1900, published in 1900.