Francis Vernon (1637?–1677) was an English traveller and author.
Born about 1637, near Charing Cross, he was son of Francis Vernon of London, and brother of James Vernon. He was admitted in 1649 to Westminster School. He matriculated on 10 November 1654 at Christ Church, Oxford. He graduated B.A. on 28 January 1658, and M.A. on 17 July 1660.
Vernom began to travel before he had taken his master's degree. During one of his voyages he was taken by pirates and sold. On his release he seems to have returned to Oxford. In 1668 he was chosen because of his experience to accompany Charles Howard, 1st Earl of Carlisle, ambassador-extraordinary to Sweden, and the king wrote to Christ Church requesting leave of absence for him.
Vernon was next appointed to go with Ralph Montagu to Paris as secretary to the embassy. His letters fell below the required standard, but he remained there till the end of 1671. He was in fact considered frivolous, filling correspondence with court and city gossip. He reported, for example, the first performances of plays by Jean Racine and Pierre Corneille in 1670 (the rival Bérénice and Tite et Bérénice).
During this time, Vernon became a point of contact between the scholars of France and England. In 1670 Christiaan Huygens, seriously ill, chose Vernon to carry out a donation of his papers to the Royal Society in London, should he die.Jean-Baptiste Colbert controlled the French Academy of Sciences closely, and in particular the circulation of publications of its academicians. Vernon copied the Mésure de la terre of Jean Picard for the Royal Society, who therefore saw it in 1671, while Colbert communicated it officially in 1676.
Among Vernon's other correspondents was Edward Pococke, copies of whose son's Latin version of Ibn-al-Tifail he presented to the Sorbonne and to Christiaan Huyghens. Another correspondent was John Collins, for whom Vernon obtained books through Jean Berthet, including works by René Descartes and Blaise Pascal. He also sent James Gregory a copy of Fermat's Diophantus. Vernon's services were recognised by his election to the Royal Society on his return to England in 1672, his proposer being Henry Oldenburg.