(Greek: “sacred marriage”), sexual (sexual intercourse) relations of fertility deities in myths and rituals, characteristic of societies based on cereal agriculture, especially in the Middle East. At least once a year, divine persons (e.g., humans representing the deities) engage in sexual intercourse, which guarantees the fertility of the land, the prosperity of the community, and the continuation of the cosmos.

As ritually expressed, there are three main forms of the hieros gamos: between god and goddess (most usually symbolized by statues); between goddess and priest-king (who assumes the role of the god); and between god and priestess (who assumes the role of the goddess). In all three forms there is a relatively fixed form to the ritual: a procession that conveys the divine actors to the marriage celebration; an exchange of gifts; a purification of the pair; a wedding feast; a preparation of the wedding chamber and bed; and the secret, nocturnal act of intercourse. In some traditions this appears to have been an actual physical act between sacred functionaries who impersonate the deities; in other traditions it appears to have been a symbolic union. On the following day the marriage and its consequences for the community are celebrated.

Some scholars have applied the term hieros gamos to all myths of a divine pair (e.g., heaven–earth) whose sexual intercourse is creative. The term, however, should probably be restricted only to those agricultural cultures that ritually reenact the marriage and that relate the marriage to agriculture, as in Mesopotamia, Phoenicia, Canaan, Israel (the Song of Solomon (Solomon, Song of) has been suggested to be a hierogamitic text), Greece, and India.