Peftjauawybast or Peftjaubast was an ancient Egyptian ruler ("king") of Herakleopolis Magna during the 25th Dynasty.
He was likely installed as governor of the town during the coregency of pharaoh Osorkon III and his son Takelot III, in 754 BCE. Some time after the death of Osorkon III, Peftjauawybast proclaimed himself king, adopting a royal titulary and starting to date monuments since his "coronation", which should have occurred in around 749 BCE. It is possible that Takelot III permitted this behavior in exchange of his nominal loyalty. Peftjauawybast also married the princess Irbastudjanefu, a daughter of Rudamun, himself brother and successor of Takelot III, thus binding to the 23rd Dynasty.
For this ruler two donation steles are known, both dated to his Year 10 (the highest ruling year known for him, although his presence on the Victory stele of Piye allows to further expand his reign length), around 740 BCE. The steles mentions another wife, queen Tasheritenese, and two daughters one of which, Pediamennebnesttawy, was a Chantress of Amun. Peftjauawybast is also attested on a golden statuette of the god Heryshaf, found in Herakleopolis.