Franc Miklošič (also Franz Miklosich; Radomerščak nr Ljutomer, Slovenia 1813 – Vienna 1891) was a leading comparative linguist and Slavic philologist. His extensive scholarly opus includes, aside from Slavic linguistics, the study of non-Slavic languages (Hungarian, Romanian, Albanian, Romany, Modern Greek, and Turkish), history, ethnography, textual criticism, and education. He substantially completed the findings of his forerunners (Jernej Kopitar, Josef Dobrovský, Aleksandr H. Vostokov, and Pavol Josef Šafárik) and may be seen as the actual founding figure of academically instituted Slavic linguistics.

Miklošič studied philosophy and law in Graz, was awarded his doctorate in 1838, and graduated in jurisprudence in 1840. Kopitar soon took him under his patronage and directed him towards Slavic philology, Lithuanian, Sanskrit, and comparative Indo-European linguistics. In 1844 Miklošič obtained the position of librarian in the Royal Library in Vienna; in 1849 he became the first professor of Slavic philology at the University of Vienna, where he worked until his retirement in 1885, making his department the leading European centre of Slavic studies. He taught many important linguists and intellectuals, e.g. Đuro Daničić, Vatroslav Jagić, Václav Vondrák, the Slovenians Janez Trdina, Matija Valjavec, Maks Pleteršnik, Karel Štrekelj, and Matija Murko; he was a supporter and friend of Vuk Karadžić. His social recognition was also significant: from 1851 he was a regular member of the Academy in Vienna; he was knighted; and in 1862 he became a life senator in the Austrian parliament. In 1848 Miklošič was politically active as the president of the national society Slovenija and co-author of the programme Zedinjena Slovenija (“United Slovenia”).

Aside from dozens of articles, Miklošič published 30 single-authored books in over 40 volumes; his oeuvre and status may be compared to those of Jacob and Wilhelm Grimm in German studies or of Friedrich Diez in Romance philology. Like Kopitar, Miklošič was convinced that Old Church Slavonic (he termed it Altslowenisch) had been the language of the Pannonian Slavs (this tenet was later refuted by August Schleicher and others). Miklošič published his dictionary of Old Church Slavonic in 1850 (Lexicon linguae slovenicae veteris dialecti; an enlarged edition, based on a greater corpus of printed or manuscript sources, was published 1862-65 as Lexicon paleoslovenico-graeco-latinum).

His groundbreaking and still valuable Slavic grammar, Vergleichende Grammatik der slavischen Sprachen, was published in four volumes over three decades (1852-83). In his methodological perfection, Miklošič compares individual Slavic languages among themselves and with Old Church Slavonic, partly also with other Indo-European languages. Also important is his research on language contacts between south-eastern European languages (Slavic, Romanian, Albanian, Modern Greek, Hungarian, and Romany) and on Latin, Greek, and Turkish influences on the Slavic languages. He published several historical-philological or entirely historical papers, as well as articles on Slavic (especially Serb or Croatian) folk poetry, and published critical editions of Old Church Slavonic and other texts.

Miklošič also authored Slovenian literary textbooks for higher gymnasium classes and influenced Slovenian linguistic handbooks. The development of a Slovenian standard language was strongly influenced by Miklošič’s equation of “Old Slovenian” with “Old Church Slavonic”, which led some Slovenian linguists, writers, and lexicographers to insert many borrowings from Old Church Slavonic into modern Slovenian.