Lieutenant-Colonel William Legge, 7th Earl of Dartmouth (22 February 1881 – 28 February 1958), styled Viscount Lewisham between 1891 and 1936, was a British hereditary peer and Conservative politician, who was Acting Lord Great Chamberlain 1928–1936.

He was commissioned as a Second lieutenant in the Staffordshire Yeomanry (Queen's Own Royal Regiment) on 11 June 1902.

While a lieutenant in the Staffordshire Yeomanry, he was appointed honorary colonel of the 7th Battalion, Duke of Wellington's Regiment, on 27 April 1910.

[4] He served with the Staffordshire Yeomanry in the Sinai and Palestine Campaign in the First World War, for which he was awarded the Territorial Decoration, and made an officer of the Order of the Nile.

As he had no surviving male issue, he was succeeded by his younger brother, Humphry Legge.