Major John Strange Spencer-Churchill (4 February 1880 - 23 February 1947) was the son of Lord Randolph Henry Spencer-Churchill and Jennie Jerome, and brother of Winston Churchill.

He was born at Phoenix Park, Dublin, Ireland and educated at Harrow School, London, England.

He married, on 8 August 1908, Lady Gwendoline Theresa Mary Bertie (20 Nov 1885 - 7 Jul 1941), the daughter of Montagu Arthur Bertie, 7th Earl of Abingdon and Gwendoline Mary Dormer.

He gained the rank of Major in the service of the Oxfordshire Yeomanry. He fought in the Boer War between 1899 and 1900, where he was mentioned in dispatches, and was wounded. He fought in the First World War, where he was again mentioned in dispatches. He was awarded the French decorations of the Croix de Guerre and the Légion d'Honneur. He was awarded the British Distinguished Service Order in 1918.

Children of Major John Strange Spencer-Churchill and Lady Gwendoline Theresa Mary Bertie:

• John George Spencer-Churchill (31 May 1909 - 1992)
• Henry Winston Peregrine Spencer-Churchill (25 May 1913 - )
• Anne Clarissa Churchill (28 Jun 1920- )

Anne Clarissa Churchill later became the second wife of the Prime Minister Sir Anthony Eden.