(ancient Hebrew, “son of a star”), the honorary surname of Simon, military leader of the anti-Roman insurrection of 132–135 in Judea.

A revolt was sparked by Roman interference in the ritual affairs of the Judeans and by the attempt of the Roman emperor Hadrian to build a Roman colony, Aelia Capitolina, with a shrine to Jupiter, on the site of Jerusalem, which had been destroyed by the Romans in the year 70. The ideological leader of the movement was the rabbi Akiba; Bar Kochba was the military organizer. In the course of the revolt, the rebels took 50 fortifications. The city of Bethar became the center of the movement. The rebellion was crushed by the Roman commander Julius Severus. Judea was made part of the province of Syria. Bar Kochba died in the defense of besieged Bethar.

Excavations made in 1952 in the Dead Sea region resulted in the discovery, in a cave of Murabbaat, of a letter written by Bar Kochba during the insurrection of 132–135 to the commander Yeshua ben Galgoula, ordering him not to harm the Christians.