Eleazar or Elazar was a priest in the Hebrew Bible, the second High Priest, succeeding his father Aaron after he died. He was a nephew of Moses.

In Judaism, the High Priest of Israel was the head of the Israelite priesthood. He played a unique role in the worship conducted in the Tabernacle and later in the Temple in Jerusalem, as well as in some non-ritual matters. Like all priests, he was required to be descended from Aaron. But unlike other priests, the high priest followed more restrictive laws, wore unique priestly garments, and was the only priest allowed to perform certain ceremonies.