Franciszek Ksawery Abgaro-Zachariasiewicz (December 1, 1770 in Stanyslaviv – June 12, 1845 in Przemysl; sometimes Zacharyasiewicz or Zacharjasiewicz) was a Polish Roman Catholic bishop of Przemysl, elevated in 1840.
He was also bishop of Tarnów (elevated in 1835).
First ordained a priest in the Armenian Catholic Church in 1795, he became a priest of the Roman Catholic Church in since 1812.
He also served as professor (1800–1827) and rector (1826/1827) of Lviv University.
In 1835 Zachariasiewicz founded theological seminary in Tarnów.
His work focused on the history of the Christian Church, Poland, and Armenians.
He was a son of Abgaro Zachary and Helena Asiewicz-Passakasow.
Her father Tomasz Asiewicz (former Osiewicz,Lith.Asevicius) is inscribed in encyclopedias of Polish nobles.
Franciszek's uncle was bishop Grzegorz Zachariasiewicz (1740-1814).Many Zachariasiewiczes were Greek-catholic priests.