Francis Dvornik (Chomýž, 14 August 1893 – Chomýž, 4 November 1975), in Czech František Dvorník, was a priest and academic, and one of the leading twentieth-century experts on Slavic and Byzantine history, and on relations between the churches of Rome and Constantinople.
Dvornik taught at Charles University in Prague, the Collège de France, and Harvard University.
Arguably Dvornik's greatest contribution to research lay in rehabilitation, from a Catholic standpoint, of the Byzantine patriarch and writer, Photius.
In 1956 Harvard University Press published a collection of Essays Dedicated to F. Dvornik on the Occasion of his 60th Birthday (Harvard Slavic studies no. 2).