Neferefre Isi (fl. 25th century BC; also known as Raneferef, Ranefer and in Greek as Χέρης, Cherês) was an ancient Egyptian pharaoh of the Fifth Dynasty during the Old Kingdom period. He was most likely the eldest son of pharaoh Neferirkare Kakai and queen Khentkaus II. He was known as prince Ranefer before he ascended to the throne.

Neferefre started a pyramid for himself in the royal necropolis of Abusir called Netjeribau Raneferef, which means "The bas of Neferefre are divine". The pyramid was never finished, with a mason's inscription showing that works on the stone structure were abandoned during or shortly after the king's second year of reign. Together with the sparsity of attestations contemporaneous with his reign, this is taken by Egyptologists as evidence that Neferefre died unexpectedly after two to three years on the throne. Neferefre was nonetheless buried in his pyramid, hastily completed in the form of a mastaba by his second successor and presumably younger brother, pharaoh Nyuserre Ini. Fragments of his mummy were uncovered there, showing that he died in his early twenties.

Little is known of Neferefre's activities beyond laying the foundations of his pyramid and attempting to finish that of his father. A single text shows that Neferefre had planned or just started to build a sun temple called Hotep-Re, meaning "Ra is content" or "Ra's offering table", which possibly never functioned as such given the brevity of the king's reign. After his death, Neferefre might have been succeeded by an ephemeral and little-known pharaoh, Shepseskare, whose relation with Neferefre remains highly uncertain and debated.

There are very few archaeological sources contemporaneous with Neferefre, a fact which is now seen by Egyptologists, including Miroslav Verner, to imply a very short reign. Verner knew of only one inscription dated to his rule. It was left by the builders of his pyramid on a corner block at the end of the corridor leading to the pyramid substructures. The inscription was written on the fourth day of the Akhet season in the year of first occurrence of the cattle count, an event consisting of counting the livestock throughout the country to evaluate the amount of taxes to be levied. It is traditionally believed that such counts occurred every two years during the Old Kingdom although recent reappraisals have led Egyptologists to posit a less regular and somewhat more frequent count. Therefore, the inscription must refer to Neferefre's first or second year on the throne, and his third year at the very latest. Finally, a few artefacts dated to Neferefre's rule or shortly after have been uncovered in his mortuary complex and elsewhere in Abusir, such as clay seals bearing his Horus name.

Some of the Abusir Papyri discovered in Khentkhaus II's temple and dating to the mid- to late Fifth Dynasty mention the mortuary temple and funerary cult of Neferefre. They constitute a written source near-contemporaneous with his reign, which not only confirmed the existence of Neferefre's pyramid complex at a time when it had not yet been identified, but also gives details regarding the administrative organisation and importance of the funerary cult of the king in Ancient Egyptian society.

Neferefre is present on several Ancient Egyptian king lists, all dating to the New Kingdom period. The earliest such list mentioning Neferefre is the Abydos King List, written during the reign of Seti I (fl. 1290–1279 BC), and where his prenomen occupies the 29th entry, between those of Neferirkare Kakai and Nyuserre Ini. During the subsequent reign of Ramses II (fl. 1279–1213 BC), Neferefre appears on the Saqqara Tablet, this time after Shepseskare, that is as a second successor to Neferirkare Kakai. Owing to a scribal error, Neferefre's name on this list is given as "Khanefere" or "Neferkhare". Neferefre's prenomen was in all probability also given on the Turin canon (third column, 21st row), which dates to the same period as the Saqqara tablet, but it has since been lost in a large lacuna affecting the document. Nonetheless, the part of the reign length attributed to Neferefre by the canon is still legible, with a single stroke sign indicating one year of reign to which a decade could in principle be added, as the corresponding sign would be effectively lost in the lacuna of the document.

Neferefre was also likely mentioned in the Aegyptiaca, a history of Egypt written in the 3rd century BC during the reign of Ptolemy II (283–246 BC) by the Egyptian priest Manetho. No copies of the Aegyptiaca have survived to this day and it is now known only through later writings by Sextus Julius Africanus and Eusebius. Africanus relates that the Aegyptiaca mentioned the succession "Nefercherês → Sisirês → Cherês" for the mid-Fifth Dynasty. Nefercherês, Sisirês and Cherês are believed to be the hellenized forms for Neferirkare, Shepseskare and Neferkhare (that is Neferefre), respectively. Thus, Manetho's reconstruction of the Fifth Dynasty is in good agreement with the Saqqara tablet. In Africanus' epitome of the Aegyptiaca, Cherês is reported to have reigned for 20 years.

Neferefre was, in all likelihood, the eldest son of his predecessor pharaoh Neferirkare Kakai with queen Khentkaus II. This is shown by a relief on a limestone slab discovered in a house in the village near Abusir and depicting Neferirkare and his wife Khentkaus with "the king's eldest son Ranefer", a name identical with some variants of Neferefre's own. This indicates that Ranefer was Neferefre's name when he was still only a crown prince, that is, before his accession to the throne.