Elazar Menachem Man Shach (Hebrew: ????? ???? ?? ??, Elazar Shach; January 1, 1899 O.S.
– November 2, 2001) was a leading Lithuanian-Jewish Haredi rabbi in Bnei Brak, Israel.
He also served as one of three co-deans of the Ponevezh Yeshiva in Bnei Brak, along with Rabbis Shmuel Rozovsky and Dovid Povarsky.
Due to his differences with the Hasidic leadership of the Agudat Yisrael in 1984, he allied with Rabbi Ovadia Yosef, who had founded the Shas party.
Later, in 1988, Shach sharply criticized Ovadia Yosef, and said that, "Sepharadim are not yet ready for leadership positions", and subsequently founded the Degel HaTorah political party representing Lithuanian (non-Hasidic) Ashkenazi Jews in the Israeli Knesset.