Yehudah Aryeh Leib Alter (1847–1905), also known by the title of his main work, the Sfas Emes, was a Hasidic rabbi who succeeded his grandfather, Rabbi Yitzchak Meir Alter, as the av beis din (head of the rabbinical court) and Rav of Góra Kalwaria, Poland (known in Yiddish as the town of Ger), and succeeded the Rebbe, Reb Heynekh of Alexander, as Rebbe of the Gerrer Hasidim.