Josif Rajačić (July 20, 1785– July 1, 1861, Cyrillic: Јосиф Рајачић, also known as Josif Rajačić-Brinski) was a metropolitan of Sremski Karlovci, Serbian patriarch, administrator of Serbian Vojvodina and baron.
Rajačić was born in Lučani (Croatia), and died in Sremski Karlovci (Vojvodina, Serbia). At the May Assembly of Serbs in Sremski Karlovci in 1848, from the balcony of the Sremski Karlovci City Hall, he was proclaimed for the Serbian patriarch. Josif Rajačić was not only the spiritual, but also the political and military leader of Serbs.
He became administrator of Serbian Vojvodina, and was on the head of the new Serb government (praviteljstvo) of Vojvodina. Rajačić formed an alliance with the Habsburgs in notion to crush the Hungarian revolution. After the Hungarians were defeated, Austrians nominated Rajačić for the civil commissary for Vojvodina.
Rajačić helped in educational development of the Serb people in the Habsburg Monarchy. In the time when he was metropolitan of Sremski Karlovci, many new Serbian schools were opened. He also opened patriarchal library and the printing house. Rajačić spent much of his energy to help that Vojvodina come under the administration of the Serb people.
On June 5, 1848, on the occasion of the inauguration of Josip Jelačić as Croatia-Slavonia ban, in the absence of Bishop Haulik, who had removed himself from Zagreb, it was in front of the Patriarch Rajačić that the Ban took his oath of office. 
- Jovan Mirosavljević, Brevijar ulica Novog Sada 1745-2001, Novi Sad, 2002.
- Drago Njegovan, Prisajedinjenje Vojvodine Srbiji, Novi Sad, 2004.
Stefan II (Stephen II)
|Metropolitan/Patriarch of Karlovci|
| Succeeded by|