The Orion Correlation Theory (OCT) is defined by Wikipedia as the idea “that there is a correlation between the location of the three largest pyramids of the Giza pyramid complex and Orion’s Belt of the constellation Orion, and that this correlation was intended as such by the original builders of the Giza pyramid complex.”
Robert Bauval is probably best known as the original promoter of the Orion Correlation Theory (OCT), which received widespread coverage when it was outlined in The Orion Mystery  written by Bauval and Adrian Gilbert and in Keeper of Genesis  written with Graham Hancock, published two years later. Bauval first published his theory in 1989 in Discussions in Egyptology(a).
Not unexpectedly, OCT generated considerable criticism as well as support, also noted on Wikipedia(g).
However, Andrew Collins has disputed the OCT and has instead offered evidence that the alignment of the three principal Giza pyramids matches more closely the ‘wing’ stars of the Cygnus constellation than the ‘belt’ of Orion!(b)
Gary A. David has expanded on the OCT of Bauval & Gilbert identifying important sites throughout Egypt that he believes constituted a more extensive reference with other heavenly bodies in what he calls the Egyptian Stellar Template(e).
David goes further and claims that he “stumbled across an Orion Correlation that the ancestral Hopi Indians constructed in Arizona from about 1050–1300 AD. In this case, every major star in the constellation corresponds to a specific masonry village site. The terrestrial replication of the celestial pattern is simply uncanny.”(f)
However, Freddy Silva has imaginatively proposed an additional OCT – in Scotland(c). He suggested that the Pyramids of Giza, and by extension, Orion’s Belt matched the layout of the three stone circles of Stenness, Brodgar and Bookan!
February 2015 saw an even more extreme idea published by Emilio Spedicato in a paper(h) with the radical proposal that the alignment of the three main Giza pyramids was not intended to be a reflection of the three stars in Orion’s belt according to the OCT, as proposed by Gilbert and Bauval, but instead were more closely matched to the arrangement of three volcanoes on Mars! He claims that these volcanoes were visible from Earth during Mars’ periodic close encounters with our planet between 7000 BC and 700 BC, during a 54-year cycle!
(a) Discussions in Egyptology, volume 13, 1989, pp. 7-18