John Henry Loftus, 3rd Marquess of Ely (19 January 1814 – 15 July 1857) was a British politician.
Born in Hill Street in Mayfair, Loftus studied at Christ Church, Oxford. As Viscount Loftus, he stood unsuccessfully as a Conservative Party candidate in Gloucester, at the 1841 UK general election. In 1844, he married Jane Hope-Vere.
Loftus won the 1845 Woodstock by-election, held on 1 May that year, but succeeded as the Marquess of Ely in September. Through his subsidiary title, Baron Loftus, he took a seat in the House of Lords.