The Marquess of Ely is a marquess in the Peerage of Ireland. The title was created in 1801 for the Earl of Ely.

The Marquess holds the subsidiary titles of Earl of Ely (1794), Viscount Loftus (1789), Baron Loftus (1785), and Baron Loftus (in the Peerage of the United Kingdom, 1801). All these titles save the last are in the Peerage of Ireland, and all were created for the same person, making the first Marquess one of the few persons to rise to the rank of Marquess without having inherited any titles.

Before the passage of the House of Lords Act 1999, the Marquess sat in the House of Lords as Baron Loftus.

Marquesses of Ely (1801)

• Charles Loftus, 1st Marquess of Ely (1738-1806)
• John Loftus, 2nd Marquess of Ely (1770-1845)
• John Henry Loftus, 3rd Marquess of Ely (1814-1857)
• John Henry Wellington Graham Loftus, 4th Marquess of Ely (1849-1889)
• John Henry Loftus, 5th Marquess of Ely (1851-1925)
• George Herbert Loftus, 6th Marquess of Ely (1854-1935)
• George Henry Wellington Loftus, 7th Marquess of Ely (1903-1969)
• Charles John Tottenham, 8th Marquess of Ely (b. 1913)