The Great Sphinx is located in the north and below the pyramids. What names their builders gave to these statues is not known. At the Great Sphinx site, the inscription on a stele erected a thousand years later, by Thutmose IV in 1400 BCE, lists the names of three aspects of the local sun deity of that period, Khepera - Rê - Atum. The inclusion of these figures in tomb and temple complexes quickly became traditional and many pharaohs had their heads carved atop the guardian statues for their tombs to show their close relationship with the powerful solar deity, Sekhmet, a lioness. Other famous Egyptian sphinxes include one bearing the head of the pharaoh Hatshepsut, with her likeness carved in granite, which is now in the Metropolitan Museum of Art in New York, and the alabaster sphinx of Memphis, Memphis, Egypt, currently located within the open-air museum at that site. The theme was expanded to form great avenues of guardian sphinxes lining the approaches to tombs and temples as well as serving as details atop the posts of flights of stairs to very grand complexes. Nine hundred with ram heads, representing Amon, were built in Thebes, where his cult was strongest.

An alternative dating theory come out of water erosion. In recent years professor Robert M. Schoch of Boston University, Colin Reader and other geologists have pointed out that the Sphinx displays evidence of prolonged water erosion. Egypt's last significant rainy period ended during the third millennium BC, and these geologists have posited that the amount of water erosion evident on the Sphinx indicates a construction date no later than the sixth or fifth millennia BC, at least two thousand years before the traditional construct.

Another speculations were generated by the works of two writers, Graham Hancock and Robert Bauval, in a series of separate and collabarative publications from the late 1980s onwards. Their claims include that the Great Sphinx was constructed in 10,500 B.C.; that its lion-shape is a definitive reference to the constellation of Leo; and that the layout and orientation of the Sphinx, the Giza pyramid complex and the Nile River is an accurate reflection or "map" of the constellations of Leo, Orion (specifically, Orion's Belt) and the Milky Way, respectively.

Their initial claims regard the alignment of the Giza pyramids with Orion ( "…the three pyramids were an unbelievably precise terrestrial map of the three stars of Orion's belt"— Hancock's Fingerprints of the Gods, 1995, p.375) are later joined with speculation about the age of the Sphinx (Hancock and Bauval, Keeper of Genesis, published 1997 in the U.S. as The Message of the Sphinx). By 1998's The Mars Mystery, they claim:

"...we have demonstrated with a substantial body of evidence that the pattern of stars that is ‘frozen’ on the ground at Giza in the form of the three pyramids and the Sphinx represents the disposition of the constellations of Orion and Leo as they looked at the moment of sunrise on the spring equinox during the astronomical ‘Age of Leo’ (i.e, the epoch in which the Sun was ‘housed’ by Leo on the spring equinox.) Like all precessional ages this was a 2,160-year period. It is generally calculated to have fallen between the Gregorian calendar dates of 10,970 and 8810 BC." (op. cit., p.189).

A date of 10,500 B.C. is chosen because they claim this is the only time in the precession of the equinoxes when the astrological age was Leo and when that constellation rose directly east of the Sphinx at the vernal equinox. They claim also that in this epoch the angles between the three stars of Orion's Belt and the horizon was an "exact match" to the angles between the three main Giza pyramids. This time period also coincides with the American psychic Edgar Cayce's "dating" of Atlantis, and together these claims are used to support the overall belief in some advanced and ancient, but now vanished, progenitor civilization.