James Spencer-Churchill, 12th Duke of Marlborough

His Grace

The Duke of Marlborough
His Grace; The Duke of Marlborough
	A portrait from 1989
Tenure	16 October 2014 – present
Predecessor	John, 11th Duke of Marlborough
Full name	Charles James Spencer-Churchill
Other titles	Earl of Sunderland (1955–1972); Marquess of Blandford (1972–2014)
Born	24 November 1955 (age 68); Oxford, Oxfordshire, England
Residence	Blenheim Palace
Spouse(s)	; Rebecca Few Brown (m. 1990; div. 1998) ; Edla Griffiths (m. 2002; sep. 2024)
Issue	George Spencer-Churchill, Marquess of Blandford; Lady Araminta Spencer-Churchill; Lord Caspar Spencer-Churchill
Heir	George, Marquess of Blandford
Father	John, 11th Duke of Marlborough
Mother	Susan Mary Hornby

Charles James Spencer-Churchill, 12th Duke of Marlborough (born 24 November 1955), styled Earl of Sunderland until March 1972 and Marquess of Blandford until October 2014, and often known as Jamie Blandford or Jamie Marlborough, is a British peer and the current Duke of Marlborough.

He is the eldest surviving son of the 11th Duke of Marlborough and his first wife, Susan Mary Hornby. As a member of the Spencer family, he is a distant relative of the war-time Conservative Prime Minister Sir Winston Churchill and of Diana, Princess of Wales, born Lady Diana Spencer. He is also a stepbrother of the late Christina Onassis, who was the stepdaughter of former First Lady Jacqueline Kennedy Onassis, who was once married to U.S. President John F. Kennedy, by the second marriage of his father with Athina Livanos. He is also a descendant of the prominent American Vanderbilt family through his great-grandmother Consuelo Vanderbilt.