Elijah ben Shlomo Zalman, (Hebrew: ר' אליהו בן שלמה זלמן‎) known as the Vilna Gaon or Elijah of Vilna and simply by his Hebrew acronym Gra ("Gaon Rabbenu Eliyahu"), ((גר"א (גאון רבינו אליהו) (b. Vilnius April 23, 1720, d. Vilaus October 9, 1797), was an exceptional Talmudist, Halachist, Kabbalist, and the foremost leader of non-hasidic world Jewry of the past few centuries. He is commonly referred to in Hebrew as ha'Gaon ha'Chasid mi'Vilna, "the saintly genius from Vilnius."

He was one of the most influential Rabbinic authorities since the Middle Ages, and – although he is counted among the sages known as the Acharonim – he is held by many authorities after him as belonging to the Rishonim (Rabbinic authorities of the Middle Ages). Large groups of people, including many yeshivas, uphold the set of Jewish customs and rites (minhag), the "minhag ha-Gra," which is named for him, and which is also considered by many to be the prevailing Ashkenazi minhag in Jerusalem. The Gaon wrote also on mathematics, being well-versed in the works of Euclid and encouraging a pupil, Rabbi Baruch of Shklov, to translate the great mathematician's works into Hebrew.

Born in Vilnius, Polish–Lithuanian Commonwealth, the Gaon displayed extraordinary talent while still a child. By the time he was twenty years old, rabbis were submitting their most difficult halakhic problems to him for legal rulings. He was a voluminous author, writing such works as glosses on the Babylonian Talmud and Shulchan Aruch known as Biurei ha-Gra ("Elaboration by the Gra"), a running commentary on the Mishnah (Shenoth Eliyahu ("The Years of Elijah")), and insights on the Pentateuch entitled Adereth Eliyahu ("The Splendor of Elijah"). Various Kabbalistic works have commentaries in his name, and commentaries on the Proverbs and other books of the Tanakh were written later on in his life. None were published in his lifetime.