Re-Horakhty as depicted on the stele of TatiaSyncretism denotes the phenomenon of unifying two or more divinities. Through these links one divinity became an extension of the other. Nevertheless, in this new combined form the original identities of the individual divinities were not lost. Examples of syncretised gods are Re-Horakhty and Ptah-Sokar-Osiris.

The process of syncretising may transcend apparent contradictory aspects: syncretistic composites of heavenly gods and netherworld gods are not unusual. Less frequent are unions of gods of different sexes.

The popular god Amun particularly often appears in syncretised forms. It has been suggested that the hidden aspect of this god (his name Amun means "the secret one") allowed him to be easily syncretised with other divinities. Already in the First Intermediate Period mention is made of the ubiquitous Amun-Re, or rather, Amun-in-his-aspect-of-Re.