Justinas Bonaventūra Pranaitis (Russian: Иустин Бонавенту́ра Пранайтис; 27 July 1861 – 28 January 1917)[1] was a Lithuanian Catholic priest.

He was a professor of Hebrew at the Saint Petersburg Roman Catholic Theological Academy and missionary in Uzbekistan.

Justinas Pranaitis was born on 27 July 1861 to a peasant family in Panenupiai [lt] near Griškabūdis in Congress Poland, client state of the Russian Empire.

[5] He claimed that it was a 17th-century painting by Bartolomé Esteban Murillo from the collection of archbishop Aleksander Gintowt-Dziewałtowski [pl].

In 1897, archbishop Szymon Marcin Kozłowski sent Pranaitis to survey the situation of Roman Catholics in Turkistan.

In 1900, he left Saint Petersburg and relocated to Tashkent for missionary work among the local Roman Catholics.

[8] He also published articles in the Lithuanian press, including Lietuvių laikraštis, Šaltinis, Vienybė, Viltis.

[9] In 1892, Pranaitis published an antisemitic tract called Christianus in Talmude Iudaeorum in Latin, adapted from his Master's thesis, under the imprimatur of the Archbishop of Mogilev, which was subsequently translated into Polish (1892), French (1892), German (1894), Russian (1911), Lithuanian (1912), Italian (1939), English (1939) and Spanish.

His credibility rapidly evaporated, however, when the defence demonstrated his ignorance of some simple Talmudic concepts and definitions, such as hullin, erubin, Baba Batra,[10][11][12] to the point where "many in the audience occasionally laughed out loud when he clearly became confused and couldn't even intelligibly answer some of the questions asked by [Beilis'] lawyer".