贝苏斯（？－前329年），波斯阿契美尼德王朝巴克特里亚总督，出身波斯贵族，大流士三世的亲戚。

在高加美拉战役中，统率主要是来自巴克特里亚所组成的波斯左翼部队。战后，贝苏斯随着大流士三世在逃往埃克巴坦那，不久与其他总督拘禁了大流士三世，并试图把大流士作为与亚历山大大帝谈和的筹码，但亚历山大亲率大军在后猛烈追赶，贝苏斯刺杀大流士后，丢下命危的波斯国王随即逃走。

西元前330年谋杀大流士三世后，贝苏斯自立为阿尔塔薛西斯五世，并试图对抗亚历山大。此时，贝苏斯仅统领巴克特里亚和忠诚低落的东部一些省份，当亚历山大对巴克特里亚步步逼近，贝苏斯开始逃亡。

For the Christian saint, see Saint Bessus.

Bessus, also known as Artaxerxes V (died summer 329 BC), was a prominent Persian Satrap of Bactria in Persia, and later self-proclaimed King of Kings of Persia. According to classical sources, he killed his predecessor and relative, Darius III, after the Persian army had been defeated by Alexander the Great. He was executed by Alexander the Great in 329 BC.