In Egyptian mythology, Ptah (also spelt Peteh) was the deification of the primordial mound in the Ennead cosmogony, which was more literally referred to as Ta-tenen (also spelt Tathenen), meaning risen land, or as Tanen, meaning submerged land. The importance Ptah was given in history can readily be understood since the name Egypt derives from a Greek spelling of the phrase Ḥ.wt-k3-Ptḥ, (sometimes transcribed Hat-ka-Ptah), meaning temple of the Ka of Ptah, the name of a temple at Memphis.

It was said (in the Shabaka Stone) that it was Ptah who called the world into being, having dreamt creation in his heart, and speaking it, his name meaning opener, in the sense of opener of the mouth. Indeed the opening of the mouth ceremony, performed by priests at funerals to release souls from their corpses, was said to have been created by Ptah. Atum was said to have been created by Ptah to rule over the creation, sitting upon the primordial mound.

In art, he is portrayed as a bearded mummified man, often wearing a skull cap, with his hands holding an ankh, was, and djed, the symbols of life, power and stability, respectively. It was also considered that Ptah manifested himself in the Apis bull.

In Memphis, Ptah was worshipped in his own right, and was seen as Atum's father, or rather, the father of Nefertum, the younger form of Atum. When the beliefs about the Ennead and Ogdoad were later merged, and Atum was identified as Ra (Atum-Ra), himself seen as Horus (Ra-Herakhty), this led to Ptah being said to be married to Sekhmet, at the time considered the earlier form of Hathor, Horus', thus Atum's, mother.

Since Ptah was the primordial mound, and had called creation into being, he was considered the god of craftsmen, and in particular stone-based crafts. Eventually, due to the connection of these things to tombs, and that at Thebes, the craftsmen regarded him so highly as to say that he controlled their destiny. Consequently, first amongst the craftsmen, then the population as a whole, Ptah also became a god of reincarnation. Since Seker was also god of craftsmen, and of re-incarnation, Seker was later assimilated with Ptah becoming Ptah-Seker.

Ptah-Seker gradually became seen as the personification of the sun during the night, since the sun appears to be re-incarnated at this time, and Ptah was the primordial mound, which lay beneath the earth. Consequently, Ptah-Seker became considered an underworld deity, and eventually, by the Middle Kingdom, become assimilated by Osiris, the lord of the underworld, occasionally being known as Ptah-Seker-Osiris.