William Pagan (1744 – March 12, 1819) was a Scottish-born merchant and political figure in New Brunswick.
He was born in Glasgow, the son of William Pagan, a dealer in sugar, and Margaret Maxwell.
By 1766, he was master of his own ship, involved in the sugar trade between the West Indies and North America.
Pagan established a business in New York City and later joined his brothers Robert and Thomas, who were based in Massachusetts, in the business of trading timber for goods from Scotland and the West Indies.
In 1783, when it became clear where the border would be established, Pagan settled in Saint John, New Brunswick.