Mathew MacNider (c.1732–1804) was a Scottish-born businessman, seigneur and political figure at Quebec. He was a Justice of the Peace and represented Hampshire County in the 1st Parliament of Lower Canada. He was the uncle of John MacNider, the pioneering 2nd Seigneur of Grand-Métis and Métis-sur-Mer.
Born at Paisley in Scotland, he was a younger son of William MacNider (b.1660), of Balsarock (or Balsarach), Ayrshire. The MacNiders had held several small estates in Ayrshire since the early seventeenth century, but spurred by the conflicts between Britain and France during the eighteenth century, Mathew and his brother William (father of John MacNider and Mrs James Johnston) moved into the import-export business. The Protestant, seafaring MacNiders quickly became well established in Scottish shipping and trading circles.
Taking advantage of the British Conquest of New France, MacNider came to the new colony around 1760, extending the reach of his business to Quebec City. The MacNiders quickly became one of the leading mercantile families there, selling Canadian timber and supplies to the Royal Navy and trading in wine and spices from Europe and the British West Indies to Quebec, London and Scotland.