Jean Alexandre Vaillant (1804 – 21 March 1886) was a French and Romanian teacher, political activist, historian, linguist and translator, who was noted for his activities in Wallachia and his support for the 1848 Wallachian Revolution. A Romantic nationalist and Freemason, he was an associate of the liberal faction in both Wallachia and Moldavia, as well as a collaborator of Ion Heliade Rădulescu, Ion Câmpineanu, Mitică Filipescu, and Mihail Kogălniceanu.
A tutor and later teacher at the Saint Sava School in Bucharest during the 1830s, he rose suspicions for his involvement in political conspiracies and was ultimately banned from Wallachia. Vaillant advocated the unification of the Danubian Principalities and other Romanian-inhabited areas, an ideal he notably expressed in his 1844 work La Roumanie. Credited with having publicized the Romanian cause in his native country during the 1850s, and with having introduced the modern references to "Romania" in international discourse, he briefly returned to Bucharest and was naturalized by the new Romanian state in 1864. The state of the Roma community was another one of Vaillant's interests, and the practice of Roma slavery led him to express support for abolitionist goals.