Mary Spratt Provoost Alexander (April 16, 1693 – April 18, 1760) was an influential colonial era merchant in New York City.
Mary was born in New York City on April 16, 1693. She was the daughter of John Spratt (c. 1650–1697) and Maria de Peyster (1659–1700), who were both from prominent families of colonial era New York.
Her father, John Spratt, was born near Glasgow, Scotland, and became a merchant in New York and a speaker for the irregular assembly during the Leisler Rebellion in 1689.
Her mother, Maria de Peyster, was from a respected Dutch family of goldsmiths. Her mother's siblings included Abraham de Peyster, the 20th Mayor of New York City, Johannes de Peyster, the 23rd Mayor of New York City, and Elizabeth de Peyster, who married John Hamilton, provincial governor of New Jersey. Her mother was first married to Paulus Schrick, and then remarried to John Spratt in 1687. After Spratt's death in 1697 she married again to one David Provoost (1670–1724), a merchant of Huguenot-Dutch ancestry who also served as the (24th) mayor of New York City. After Mary's mother died in 1700, the Spratt children went to live with their maternal grandmother, Cornelia DePeyster, a major merchant rated as one of the wealthiest people in New York in 1695. Her maternal grandfather was Johannes de Peyster Sr. (c. 1600–c. 1685), a Dutch merchant who emigrated to New Amsterdam.
Mary's life was divided between caring for her growing family, continuing the Provoost mercantile enterprises, and supporting her husband's political career. Mary played a pivotal role in the case of John Peter Zenger. She traveled to Philadelphia and successfully convinced prominent lawyer Andrew Hamilton to represent Zenger in his New York libel case.
Under her leadership, the Provoost business grew extensively. She imported goods on such a large scale that it was said that hardly a ship docked in New York City without a consignment of goods for her. She sold these goods in her own store and, during the French and Indian Wars, supplied William Shirley’s Fort Niagara expedition with food, tools, cannon, and boats. In 1743 her fortune was estimated at 100,000 pounds, and she and her family lived in a mansion on Broad Street. One of her sons, William Alexander, Lord Stirling, became her business partner.