The Holiness code is used in biblical criticism to refer to Leviticus chapters 17–26, and sometimes passages in other books of the Pentateuch, especially Numbers and Exodus. It is so called due to its highly repeated use of the word holy. Kadash is usually translated as "holy", but originally meant "set apart", with "special", "clean/pure", "whole" and "perfect" as associated meanings. The term Holiness Code was first coined as the Heiligkeitsgesetz by German theologian August Klostermann in 1877. Critical biblical scholars have regarded it as a distinct unit and have noted that the style is noticeably different from the main body of Leviticus. Unlike the remainder of Leviticus, the many laws of the Holiness Code are expressed very closely packed together, and very briefly.

Jacob Milgrom was a prominent American Jewish Bible scholar and Conservative rabbi. Milgrom's major contribution to biblical research was in the field of cult and worship. Although he accepted the documentary hypothesis, contrary to the classical bible critics, he traced a direct line of development from the Priestly Code (P), to the Holiness Code (H), to the cultic innovations of Ezekiel, to the cultic writings of the Dead Sea sect and finally to Jewish law (halacha) of the Mishnah and Talmud. Best known for his comprehensive Torah commentaries and work on the Dead Sea Scrolls, he also published extensively on the Book of Ezekiel.