Agha Mohammad Khan Qajar, also known by his regnal name of Agha Mohammad Shah, was the founder of the Qajar dynasty of Iran, ruling from 1789 to 1797 as Shah. Originally a chieftain of the Quwanlu branch of the Qajar tribe, Agha Mohammad Khan was enthroned as the king of Iran in 1789, but was not officially crowned until March 1796, having deposed Lotf Ali Khan of the Zand dynasty in 1794. Agha Mohammad Khan Qajar was famously the eunuch Monarch, being castrated as a toddler upon his capture by Adel Shah Afshar, and hence was childless. He was assassinated on 17 June 1797, and was succeeded by his nephew, Fath-Ali Shah Qajar.

The Qajar dynasty was an Iranian dynasty founded by Mohammad Khan of the Qoyunlu clan of the Turkoman Qajar tribe.