Meir Berlin, later Hebraized to Meir Bar-Ilan, (1880-1949), born Volozhin, Lithuania, died Jerusalem, Israel) was an Orthodox rabbi and leader of Religious Zionism, the Mizrachi movement in USA and British Mandate of Palestine. He inspired the founding of Bar Ilan University in Israel which is named for him.

He was a scholar of Talmud as well as the son of an important Haredi rabbi, Rabbi Naftali Zvi Yehuda Berlin, known as the Netziv, who was the head of the famous Volozhin Yeshiva in Lithuania. He studied in the traditional yeshivas of Volozhin, Telshe, Brisk and Novardok, where he learned with his grandfather, the renowned Rabbi Yechiel Michel Epstein. Gaining Semicha in 1902, he travelled to Germany where he became acquainted with a more modern form of Orthodox Judaism that had a more tolerant attitude to secular education and to political Zionism (although such attitudes were also present in the Lithuania of his youth, and in his grandfather). There, he attended the University of Berlin.

In 1905 he joined the Mizrachi movement, representing it at the Seventh Zionist Congress, voting against the "Uganda Proposal" to create a "temporary" Jewish "homeland" in Uganda in East Africa, as suggested by Great Britain.

In 1911 he was appointed secretary of the world Mizrachi (Religious Zionism) movement. In 1913 he came to the United States and developed local Mizrachi groups into a national organisation, chairig the 1st U.S. Mizrachi convention, held in Cincinnati in 1914. In 1915 he became president of the U.S. Mizrachi, holding the position until 1928, whereupon he became honorary president. He was an active member of the JDC during World War I, also serving as vice president of the Central Relief Committee of New York City in 1916. He founded the Mizrachi Teachers Institute in 1917. In 1925 he became a member of the Board of Directors of the Jewish National Fund devoted to financing the rebuilding of the Jewish homeland in the then British Mandate of Palestine. In 1923, he also briefly served as acting president what is now Yeshiva University during the temporary absence of its then-president, Bernard Revel.

In 1923 he moved to Jerusalem. He opposed the Palestine partition plan in 1937, and of the British White Paper of 1939, he advocated civil disobedience and non-cooperation by the Jews with the British.

He was president of the Talmudical Encyclopedia, on the board of directors of the Mizrachi Bank, the founder and editor of Hatzofeh in Tel Aviv in 1939, and authored:

• Fun Volozhin bis Yerushalayim (autobiography) in 2 volumes (in Yiddish, NYC in 1933; in Hebrew, Tel Aviv, 1939-40)
• Bishvil ha-Techiah (Tel Aviv, 1940)
• Rabann shel Yisrael (NYC, 1943)

He was also the editor of the Talmudical Encyclopedia Volume I (Jerusalem, 1946) and Volume II (published posthumously in 1949). He wrote articles on Talmudic subjects for various periodicals and died in Jerusalem, Israel, on April 17, 1949.

He inspired the founding of Bar-Ilan University near Tel Aviv, founded in 1950, by the American Mizrachi movement, which is named for him: "The name Bar-Ilan was chosen, in honor of Rabbi Meir Bar-Ilan (Berlin), a spiritual leader who led traditional Judaism from the ashes of Europe to rebirth and renaissance in the Land of Israel." Bar-Ilan Street in Jerusalem is also named for him.