Rabbi Eliezer ben Hyrcanus, known as Rabbi Eliezer HaGadol, a Tanna of the second generation, was one of the five leading disciples of Rabban Yochanan ben Zakkai. The son of a wealthy landowner, he began studying late, at twenty-two or twenty-eight depending on the source; against his father's wishes he left for Jerusalem and entered Rabban Yochanan's yeshiva, studying diligently despite great poverty. He became one of the greatest sages of his generation and the fifth most frequently cited sage in the Mishnah.

His teacher described him as "a plastered cistern that loses not a drop": he faithfully transmitted all he had received. Brother-in-law of Rabban Gamliel of Yavneh, whose sister Imma Shalom he married, and frequent disputant of Rabbi Yehoshua ben Chanania, he headed a yeshiva and court in Lod. In the famous dispute over the "oven of Achnai" he invoked miracles and even a heavenly voice to prove he was right, but the majority ruled that "the Torah is not in heaven"; he was then set apart.

He was the teacher of Rabbi Akiva. Tradition attributes Pirkei deRabbi Eliezer to him. According to tradition he rests in Alma.