Lewis Hippolytus Joseph Tonna (3 September 1812 – 2 April 1857) was an English polyglot and campaigner on behalf of evangelical protestantism. He served as a secretary of the Royal United Services Institution and had antiquarian and numismatic interests.

Born in Liverpool, son of the Spanish vice-consul and consul for the Kingdom of the Two Sicilies, his father died in 1828 while he was a student in Corfu and he was compelled to find employment as an interpreter aboard the Hydra. His mother was the daughter of H.S. Blanckley consul-general in the Balearic Islands. He served as interpreter and 'acting schoolmaster' on various ships until returning to England in 1835. A period of employment aboard the Britannia brought him in contact wit Sir Pulteney Malcolm who helped him obtain a position as acting director and later secretary of the Royal United Services Institute.^[1]

Tonna was married to Charlotte Elizabeth Browne, widow of Captain George Phelan, in 1841 and the two were prolific pamphleteers for the evangelical Protestant cause.^[1] When Giacinto Achilli was interned following the fall of the Roman Republic, Tonna was prominent in the campaign for his release and return to England.^[2] Following Charlotte's death in 1846, in 1848 he married Mary Anne Dibdin, daughter of Charles Dibdin (the younger). Neither marriage produced children and Tonna died in London.^[1]

Tonna wrote several small books and pamphlets including Erchomena, or Things to Come (1847), Nuns and Nunneries: Sketches compiled entirely from Romish Authorities (1852), The Real Dr. Achilli: a few more words with Cardinal Wiseman (1850), and added a biographical memoir in the third edition of the book by his first wife Life of Charlotte Elizabeth (1848).^[1]

• Fellow of the Society of Antiquaries;^[1]
• Fellow of the Royal Geographical Society (1855).^[1]

• Gilley, S. (2004) "Achilli, (Giovanni) Giacinto (b. c.1803)", Oxford Dictionary of National Biography, Oxford University Press, accessed 22 July 2007 (subscription required)
• Laughton, J. K. (2004) "Tonna, Lewis Hippolytus Joseph (1812–1857)", rev. Stephen Gregory, Oxford Dictionary of National Biography, Oxford University Press, accessed 23 July 2007 (subscription required)
• Lewis, D. M. (ed.) (1995). The Blackwell Dictionary of Evangelical Biography, 1730–1860 (2 vols. ed.). {{cite book}}: |author= has generic name (help)

• s:Tonna, Lewis Hippolytus Joseph