Yisrael Alter (Polish: Izrael Alter, Hebrew: ישראל אלתר; October 1895 – 20 February 1977), also known as the Beit Yisrael, after the works he authored, was the fifth Rebbe of the Hasidic dynasty of Ger, a position he held from 1948 until 1977.

Yisrael Alter was born in Poland on the holiday of Isru Chag Sukkot (1894), the third son of Rabbi Avraham Mordechai Alter. Until the age of ten, he studied with his grandfather, Rabbi Yehuda Aryeh Leib Alter, and was already known as a prodigy. He was particularly known for his strict adherence to time. At thirteen, he became engaged to Chaya Sarah, the daughter of his cousin Rabbi Yaakov Meir Biderman, and married her in 1910. They had two children, a daughter named Rivka Yocheved, born in 1917, and a son, Yehuda Aryeh Leib (Leibele), born in 1921.

Following his father's request for assistance, Yisrael began leading a group of young scholars within the Gerrer community, guiding them with spiritual teachings and personal instructions. This was confirmed by his brother, Rabbi Pinchas Menachem Alter, in a public address two weeks before his death.

In the month of Shevat 1932, Yisrael joined his father on his fourth journey to the Land of Israel and again in 1935 on the fifth trip. During the Holocaust, Yisrael fled with his father from Poland, eventually reaching Israel on the 8th of Nisan 1940. His immediate family—his wife and children—were murdered by the Nazis, as were most of the Gerrer Hasidim who lived in Poland. After his father's death in 1948, Yisrael was appointed as his successor in the Gerrer Hasidic dynasty. In the same year, he remarried Perel (Charlotte), the daughter of David Weinfeld. They had no children.

As the new Gerrer Rebbe, Yisrael worked to rebuild the Hasidic movement, increasing its influence and shaping its future direction. He gathered the remaining Gerrer Hasidim who had settled in Israel before the war, along with Holocaust survivors, and sought to bring back those who, or whose families, had distanced themselves from the Hasidic movement.

He is considered one of the major figures in the rebuilding of the Haredi community after the Holocaust, particularly in establishing public norms regarding modesty, gender segregation, and separation from secular culture. His influence extended far beyond Gerrer Hasidim, attracting followers from other segments of society.

Yisrael’s public activities were primarily within the framework of Agudat Yisrael. He placed great emphasis on education, working with other Haredi leaders to establish the Independent Education System, an autonomous religious education framework. Additionally, he was instrumental in founding the Haredi daily newspaper, Hamodia, and worked tirelessly to secure its financial stability.

The importance Yisrael placed on education and religious journalism can be seen in the fact that during his leadership, he avoided fundraising campaigns for any cause, except for a single fundraiser for the newspaper Hamodia and another for Independent Education.