Peithon or Pithon (Greek: Πείθων or Πίθων, about 355 – 314 BC) was the son of Crateuas, a nobleman from Eordaia in western Macedonia. One of the bodyguards of Alexander the Great, later satrap of Media and one of the diadochi.
Peithon was named one of the seven (later eight) Somatophylakes "bodyguards" of Alexander in 335 BC. After Alexander's death in 323 BC, Peithon was made the satrap of Media, the strategically important region that controlled all roads between east and west. Actually, the satrapy was too large for one man; Peithon would be very powerful, and could destabilize the entire empire. Therefore, he had to give up the northern part, which was given to Atropates, from then on known as Media Atropatene.
The soldiers who remained in the eastern part of Alexander's realm after his death grew agitated by their lengthy stay abroad, and began spontaneous revolts. The regent Perdiccas sent Peithon to subdue the revolters. He was given a contingent of Macedonians. Peithon easily defeated his opponents and accepted their capitulation. His men, however, having hoped to plunder, massacred their opponents.
In the summer of 320 BC, Peithon, Seleucus, and Antigenes murdered Perdiccas and started negotiating with their opponents. Ptolemy suggested that Peithon be made the new Regent, but the other diadochi would not accept this. Therefore Antipater was chosen to be the new Regent.
After the death of Antipater, Peithon expanded his realm. He invaded the satrapy of Parthia and made his brother Eudemus the new satrap. From 317 BC however, the other eastern satraps united against Peithon and drove him out. The armies of the eastern satrapies, including contingents from India sent by another Peithon, son of Agenor, the satrap of the Indus, were joined by Eumenes who had been appointed by the new regent Polyperchon to subdue Antigonus. Peithon was saved by Antigonus who beat both Eumenes and his new allies at a battle near Susa. Following the Second War of the Diadochi, Peithon was among the most powerful diadochi in the eastern part of the Empire and he started to rebuild his realm. Antigonus didn't like his new rival and tricked Peithon to come to his court, where he had him executed.