Judah ha-Nasi or Judah I, known simply as Rebbi or Rabbi, was a second-century rabbi and chief redactor and editor of the Mishnah. He lived from approximately 135 to 217 CE. He was a key leader of the Jewish community in Roman-occupied Judea after the Bar Kokhba revolt.

The Mishnah or the Mishna is the first major written collection of the Jewish oral traditions that are known as the Oral Torah. It is also the first major work of rabbinic literature. The Mishnah was redacted by Judah ha-Nasi probably in Beit Shearim or Sepphoris between the ending of the second century and the beginning of the 3rd century CE in a time when the persecution of Jews and the passage of time raised the possibility that the details of the oral traditions of the Pharisees from the Second Temple period would be forgotten.