Sir Thomas Grosvenor, 3rd Baronet (20 November 1656 – 2 July 1700) was an English Member of Parliament, and an ancestor of the modern day Dukes of Westminster.

Roger had been the son and heir of Sir Richard Grosvenor, 2nd Baronet, and therefore, Thomas succeeded to the baronetcy upon the death of his grandfather on 31 January 1665.

[4] The money for this venture came partly from the estates, and also from coal and lead mines, and from stone quarries in north Wales, that were owned by the family.

In 1685, he became Mayor of Chester, and later that year, raised a troop of horses to support James II in the Monmouth Rebellion.

Mary was the daughter of Alexander Davies, a scrivener (scribe), and she had inherited substantial land to the west of London from her great-uncle Hugh Audley.

Grosvenor's surviving sons were all under age at the time of his death; Sir Richard Myddelton, 3rd Baronet, and Thomas and Francis Cholmondeley were appointed as their guardians.