In Aztec mythology, Tōnacācihuātl (Nahuatl pronunciation: [toːnakaːˈsiwaːt͡ɬ]) was a creator and goddess of fertility, worshiped for peopling the earth and making it fruitful.

Some read this root as tonacā (without the long 'o'), consisting of nacatl, meaning "human flesh" or "food", with the possessive prefix to ("our").

"[6] In 1629, Hernando Ruiz de Alarcón also reported the use of the goddess's name in ritual planting prayers, in which a seed of corn is entrusted to the earth deity Tlaltecuhtli by a shaman who calls the kernel nohueltiuh Tōnacācihuātl ("my sister, the Lady of Abundance").

[11] Ometecuhtli and Omecihuatl, or Tonacatecuhtli and Tonacacihuatl govern the divine nature divided into two gods (it is convenient to know man and woman; the man, who created and governed everything that is of the masculine gender and the woman everything that belonged to the feminine gender).

Omecihuatl, for her part, gave birth to many children on the Thirteen Heavens with Ometecuhtli, and after all these births she had given birth to a flint, which in their language they call tecpatl, from which the other gods were amazed and frightened, their children agreed to throw it out of the heavens to the said flint, and thus they put into action, and that it fell in a certain part of the earth, called Chicomoztoc, which means 'Seven Caves', and that then one thousand and six hundred gods and goddesses came out of it, the Nauhtzonteteo that spread over the face of the earth, the sea, the underworld, and the heavens.