George Charles Spencer-Churchill, 8th Duke of Marlborough, DL (13 May 1844 – 9 November 1892), styled Earl of Sunderland until 1857 and Marquess of Blandford between 1857 and 1883, was a British peer.

In 1863 Marlborough joined the British Army, purchasing a commission in the rank of Lieutenant in the Royal Horse Guards.

They divorced on 20 November 1883, shortly after Marlborough inherited the dukedom upon the death of his father,[2] having parented four children: While married to Albertha, he fathered an illegitimate son Guy Bertrand, later known as Guy Bertrand Spencer (born on 4 November 1881, 9 days before his half-brother),[7] by Edith Peers Williams[8][9] who was still married to Heneage Finch, 7th Earl of Aylesford.

In an attempt to pressure Lord Aylesford to drop his divorce suit, Lady Aylesford and Marlborough's younger brother, Lord Randolph Churchill, threatened the Princess of Wales that they would subpoena the Prince of Wales (who was touring India at the time) as a witness in the divorce.

The 8th Duke of Marlborough died in 1892, aged 48 at Blenheim Palace,[1] and was succeeded by his only legitimate son, Charles.