In ancient Egyptian mythology, Aker is the personification of the earth as well as the Netherworld. The first apperance of Aker appears in the Pyramid Texts of the Old Kingdom.

Typically depicted as a strip of land with human head, or also as a double lion or double sphinx with two heads, he is the guardian of the entrance to and from the Netherworld, although the literature indicates some ambivalence in the guardianship. To the deceased, he can be either threatening or helpful. Aker's apperances are limited almost entirely to the Books of the Netherworld, with the exception of the Book of the Earth, with limited visibility. He had no indepedent cult that worshipped him.