Leviticus 18 deals with a number of sexual activities considered abominable, including incest and bestiality. The chapter also condemns Moloch worship. It is part of the Holiness Code, and its sexual prohibitions are largely paralleled by Leviticus 20, except that chapter 20 has more emphasis on punishment.

The Book of Leviticus is the third book of the Torah and of the Old Testament, also known as the Third Book of Moses. Many hypotheses presented by scholars as to its origins agree that it developed over a long period of time, reaching its present form during the Persian Period, from 538 to 332 BC, although this is disputed.