William Grant (June 15, 1744 – October 5, 1805) was a Scottish-born businessman, seigneur and political figure in Lower Canada.
In 1759, he was hired by a relative, Robert Grant, who was supplying the Royal Navy at Quebec and sent there as an agent of the company.
He also acquired property in the province, including land holdings at Saint-Roch, which he was able to have designated a fief; he also purchased the sub-fief of La Mistanguienne (also known as Montplaisir) and the seigneury of Aubert-Gallion.
Mrs Grant's daughter by her first marriage inherited her father's title, becoming the 4th Baroness de Longueuil.
[1] Grant took part in the defence of the town of Quebec during the American invasion of 1775-6 and some of his property was damaged during this period.