Rabbi Moses Sebulun Margolies (April 1851 – August 25, 1936) (Hebrew: משה זבולן מרגליות) was a Russian-born American Orthodox rabbi, who served as senior rabbi of Congregation Kehilath Jeshurun on the Upper East Side of the New York City borough of Manhattan. In its obituary, The New York Times described Rabbi Margolies as the "dean of orthodox rabbis in North America," a "Zionist leader and Jewish educator."
Margolies was born in Kroza, Russia in April 1851 and received his rabbinical training at the yeshivas in Kroza and Białystok. He received semicha from Rabbi Yomtov Lipman Heilpern, the Oneg Yom Tov. He became the rabbi of Sloboda at age 26, serving there until he was summoned to Boston in 1889 to serve as the chief rabbi for that city's Orthodox Jewish community. He came to New York City in 1906 to serve as rabbi of Congregation Kehilath Jeshurun, described by The New York Times as "one of the largest and most influential Orthodox congregations in the country."
As part of the anti-Nazi Boycott of 1933, Rabbi Margolies rose from his sickbed to address the overflow crowd at Madison Square Garden on March 27, 1933, bringing the crowd of 20,000 to its feet with his prayers that the antisemitic persecution cease and that the hearts of Israel's enemies should be softened.
Rabbi Margolies died at age 85 on August 25, 1936 at the Carlton Hotel in Belmar, New Jersey, with his wife, son and daughter at his bedside. He had been stricken with pneumonia a week before his death. Funeral ceremonies were to be held the following day at Congregation Kehilath Jeshurun.