Menkauhor Kaiu (also known as Ikauhor and in Greek as Mencherês) was an Ancient Egyptian pharaoh of the Old Kingdom period. He was the seventh ruler of the Fifth Dynasty at the end of the 25th century BC or early in the 24th century BC.
Menkauhor ruled for possibly eight or nine years, following king Nyuserre Ini, and was succeeded in turn by Djedkare Isesi. Although Menkauhor is well attested by historical sources, few artefacts from his reign have survived, and he is one of the least known pharaohs of the Fifth Dynasty. Consequently, his familial relation to his predecessor and successor is unclear, and no offspring of his have been identified. Khentkaus III may have been Menkauhor's mother, as indicated by evidence discovered in her tomb in 2015.
Beyond the construction of monuments, the only known activity dated to Menkauhor's reign is an expedition to the copper and turquoise mines in Sinai. Menkauhor ordered the construction of a sun temple, called the "Akhet-Ra", meaning "The Horizon of Ra". The last ever to be built, this sun temple, known from inscriptions found in the tombs of its priests, is yet to be located. Menkauhor was buried in a small pyramid in Saqqara, which the Ancient Egyptians named Netjer-Isut Menkauhor, "The Divine Places of Menkauhor". Known today as the Headless Pyramid, the ruin had been lost under shifting sands until its rediscovery in 2008.
The figure of Menkauhor was at the center of a long lasting funerary cult until the end of the Old Kingdom period, with at least seven agricultural domains producing goods for the necessary offerings. The cult of a deified Menkauhor, then known by the titles "Strong Lord of the Two Lands, Menkauhor the Justified" reappeared during the New Kingdom period (c. 1550– c. 1077 BC), and lasted until at least the Nineteenth Dynasty (c. 1292– c. 1077 BC), some 1200 years after his death