William McDonell Dawson (1822 – August 9, 1890) was a Quebec businessman and political figure, and a Scottish Roman Catholic.
He was born in Redhaven, Banffshire, Scotland in 1822 and came to Nepean Township near Bytown around 1836.
During his first term in office, he travelled to London in an attempt to secure financing for a transcontinental railroad.
His brother Simon James served in the Ontario legislature and the Canadian House of Commons.
Another brother Aeneas McDonell Dawson was a priest and author at Ottawa.