Vatroslav Jagić[a] (Serbo-Croatian pronunciation: [ʋâtroslaʋ jǎːɡitɕ];[2][3] July 6, 1838 – August 5, 1923) was a Croatian scholar of Slavic studies in the second half of the 19th century.

He polemicised against the Rijeka Philological School through scathing reviews of Fran Kurelac [hr]'s books Recimo koju [Let's Say a Few Words] (1860) and Fluminensia (1862),[4] and especially against the dominant Zagreb Philological School, represented by Adolfo Veber Tkalčević and Bogoslav Šulek, regarding the problems of orthography and pronunciation (Naš pravopis [Our Orthography], 1864).

], 1859), in the 1864 article he criticised Zagreb School's usage of the -ah ending in the genitive plural form of nouns, as it lacked basis in the history of language, instead arguing for the -â ending, in line with the norm espoused by Vuk Karadžić and his followers; he also argued for introducing moderate elements of phonemic orthography to the otherwise morphological and etymological norm of the Zagreb School.

[5] In his arguments he introduced the methods of comparative linguistics in Croatia,[6] and their influence paved the way for the Vukovian standard prevailing over Zagreb School's.

In his work on Old Church Slavic he concluded and proved that the language did not originate in the central plains of Pannonia, as it was previously claimed by Jernej Kopitar and Franz Miklošič, but in southern Macedonia.

[11] In his later years he also studied the life and works of Juraj Križanić (1618–1683), a Dominican priest that had shown considerable interest in Pan-Slavism and cooperation between Catholicism and Orthodoxy.

Complete bibliographies of Jagić's works have been published in Izabrani kraći spisi (1948) and in Zbornik o Vatroslavu Jagiću II: Bibliografija / Literatura (ed.