Avraham Abba Leifer (1918 – 7 January 1990) was the second Rebbe of the Pittsburg Hasidic dynasty and the instigator for the relocation of the Hasidut from its original location in Pittsburgh, Pennsylvania to the Israeli coastal city of Ashdod. He was widely known for his yiras Shamayim (fear of Heaven), humility and friendliness toward Jews of all backgrounds.

Avraham Abba Leifer was born in Krula, Hungary to Rabbi Yosef Leifer, the grandson of Rabbi Mordechai of Nadvorna and a direct descendant of Grand Rabbi Meir the Great of Premishlan, a disciple of the Baal Shem Tov. He was the oldest of four brothers; the others were Yissachar Ber, Mordechai and Yitzchak Eisik. Yitzchak Eisik died at the age of 11.

Before the First World War, Rabbi Yosef Leifer traveled to America to raise money to marry off his orphaned nieces. When he came to the city of Pittsburgh, Pennsylvania, the local Hasidic community asked him to stay and serve as their spiritual leader. Rabbi Yosef agreed and brought over his entire family, naming himself the Pittsburger Rebbe. He served as Rebbe for more than four decades, until his death on 7 March 1966 (Shushan Purim 5726).