Andrew Ramsay was a merchant in Alexandria. He and William Ramsay were twin sons of Patrick and Elizabeth Ramsay. Andrew was the husband of Catherine Graham Ramsay (d. 1844), daughter of Richard Graham (d. 1796) and Jane Brent Graham. The Ramsay brothers dined at Mount Vernon on 26 Feb. 1799.

Andrew and his brother William appear to have been partners in the same mercantile firm. They imported goods from London and sold Madeira wine, port wine, tobacco, gun powder and other items. The firm declared bankruptcy in 1801 (see Miller, Artisans and Merchants of Alexandria, 2:58-59).

In the 1790s GW purchased nails from Andrew and William (see, for instance, Ledger B, 337, 342, 345).