His mother sought to make provision for him by marriage to wealthy heiresses. He married firstly, at Greenwich in October 1466, Lady Anne Holland (1461c. 1474), the only daughter of
Henry Holland, 3rd Duke of Exeter, and
Anne of York. His mother-in-law was the second child and eldest surviving daughter of
Richard Plantagenet, 3rd Duke of York, and
Cecily Neville, thus sister to his mother's second husband King
Edward IV. After Anne Holland died young without issue, Thomas married secondly, by
papal dispensation 5 September 1474,
Cecily Bonville,
7th Baroness Harington of Aldingham and 2nd Baroness Bonville, the wealthiest heiress in England. Cecily Bonville, born in 1461, was the daughter and heiress of
William Bonville, 6th Baron Harington, by his wife
Katherine Neville, daughter of
Richard Neville, 5th Earl of Salisbury. Katherine was sister to the late
Earl of Warwick and thus aunt to his daughters. By his second wife Grey had seven sons and seven daughters: • Lord Edward Grey, eldest son and heir, who predeceased his father, and was buried in the church of
St Clement Danes,
London. He married Anne (née Jerningham), daughter of Sir Edward Jerningham (died 6 January 1515) of
Somerleyton,
Suffolk, by Margaret Bedingfield (died 24 March 1504), by whom he had no issue. After his death she remarried four times, firstly to a husband surnamed Berkeley; secondly to
Henry Barley (died 12 November 1529) of
Albury, Hertfordshire; thirdly to
Sir Robert Drury; and fourthly to
Sir Edmund Walsingham. • Anthony Grey, who predeceased his father. •
Thomas Grey, 2nd Marquess of Dorset (22 June 147722 June 1530), who married firstly Eleanor St John, by whom he had no issue, and secondly
Margaret Wotton, widow of William Medley, esquire, and daughter of Sir Robert Wotton by Anne Belknap, daughter of Henry Belknap esquire, by whom he had four sons, including
Henry Grey, 1st Duke of Suffolk, father of
Lady Jane Grey, and four daughters. • Sir Richard Grey, who married Florence Pudsey. He is mentioned in the will of his brother, Sir John Grey. • Sir John Grey, who married firstly Elizabeth Catesby, widow of Roger Wake (died 16 May 1504) of
Blisworth,
Northamptonshire, and daughter of Sir William Catesby, and secondly Anne Barley or Barlee (died 1557 or 1558), widow of
Sir Robert Sheffield of
Butterwick,
Lincolnshire,
Speaker of the House of Commons. Grey apparently had no issue by either of his wives, as his will dated 3 March 1523 makes no mention of children. After Grey's death his widow, Anne, married Sir
Richard Clement (d.1538) of
Ightham Mote,
Kent. •
Leonard Grey, 1st Viscount Grane (c. 149028 June 1541), According to Richardson, Grey married firstly Elizabeth Arundel, widow of Sir Giles Daubeney, and secondly Eleanor Sutton, daughter of
Edward Sutton, 2nd Baron Dudley by Cecily Willoughby, daughter and coheiress of Sir William Willoughby; however according to Lyons it is unclear whether Grey ever married. He is mentioned in the will of his brother, Sir John Grey. He served as
Lord Lieutenant of Ireland. • George Grey, in holy orders. He is mentioned in the will of his brother, Sir John Grey. • Cecily Grey (buried 28 April 1554 at
St Margaret's, Westminster), who married
John Sutton, 3rd Baron Dudley. • Bridget Grey, believed to have died young. •
Dorothy Grey, Baroness Montjoy (1480–1552), who married firstly
Robert Willoughby, 2nd Baron Willoughby de Broke, by whom she had issue, and secondly
William Blount, 4th Baron Mountjoy. •
Elizabeth Grey, who married
Gerald FitzGerald, 9th Earl of Kildare. • Margaret Grey, who married Richard Wake, esquire, She is mentioned, as 'Margaret Grey', in the will of her brother, Sir John Grey. •
Eleanor Grey (or "Elizabeth") Grey (died by December 1503) who was the first wife of Sir
John Arundell (1474–1545) of
Lanherne, Cornwall, Receiver General of the
Duchy of Cornwall and "the most important man in the county". • Mary Grey (149322 February 1538), who married
Walter Devereux, 1st Viscount Hereford. ==Titles==