Marquess of Rockingham, in the County of Northampton, was a title in the Peerage of Great Britain. It was created in 1746 for Thomas Watson-Wentworth, 1st Earl of Malton. The Watson family descended from Lewis Watson, Member of Parliament for Lincoln. He was created a Baronet, of Rockingham Castle in the County of Northampton, in the Baronetage of England in 1621. In 1645 he was further honoured when he was raised to the Peerage of England as Baron Rockingham. The third Baron served as Lord-Lieutenant of Kent. In 1714 he was created Baron Throwley, Viscount Sondes and Earl of Rockingham in the Peerage of Great Britain. His eldest son Edward Watson, Viscount Sondes, predeceased him and he was succeeded by his grandson, the second Earl. The second Earl was Lord-Lieutenant of Kent before his early death in 1745. He was childless and was succeeded by his younger brother, Thomas. He had previously represented Canterbury in Parliament.

Thomas Watson-Wentworth, 1st Marquess of Rockingham, KB, PC (I) of Wentworth Woodhouse, Yorkshire was a British Whig politician who sat in the House of Commons from 1715 until 1728 when he was raised to the Peerage as Baron Malton.