The priestly breastplate or breastpiece of judgment was a sacred breastplate worn by the High Priest of the Israelites, according to the Book of Exodus. In the biblical account, the breastplate is termed the breastplate of judgment, because the Urim and Thummim were placed upon it. These elements of the breastplate are said in the Exodus verse to carry the judgement of God concerning the Israelites at all times.

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.