Major William George Sydney Cadogan MVO (31 January 1879 – 12 November 1914) was a British Army officer killed in the First World War.

A son of the 5th Earl Cadogan, he had previously served in the Boer War, and was equerry to the Prince of Wales (later Edward VIII) from 1912 to 1914.

[2] From November 1896, he was a second lieutenant in the 4th (Eton College) Volunteer Battalion of The Oxfordshire Light Infantry.

[4] Cadogan saw action in the Second Boer War, where he was present at the Relief of Kimberley and for operations in the Transvaal, the Orange Free State, and the Cape Colony.

They departed Southampton on 7 October 1914 and arrived in Ostend the following day, subsequently joining the 6th Cavalry Brigade.

[17] The inscription on his gravestone reads: TELL ENGLAND YE THAT PASS THIS WAY THAT HE WHO RESTS HERE DIED CONTENT.