The Kingdom of Sophene (Armenian: Ծոփքի Թագավորութիւն) was an ancient Armenian kingdom. Founded around the 3rd century BC the kingdom maintained independence until around 90 BC when Tigranes the Great conquered the territories as part of his empire. An offshoot of this kingdom was the Kingdom of Commagene, formed when the Seleucids detached Commagene from Sophene.
Sophene was part of the kingdom of Urartu in the 8th-7th centuries BC. After unifying the region with his kingdom in the early 8th century BC, king Argishti I of Urartu resettled many of its inhabitants to his newly built city of Erebuni.
After Alexander the Great's campaigns in 330s BC and the subsequent collapse of the Achaemenid Empire, it became one of the first regions of Armenia to be exposed to Greek influence and adopted some aspects of Greek culture. Sophene remained part of the newly independent kingdom of Greater Armenia. Around the 3rd century BC, the Seleucid Empire forced Sophene to split from Greater Armenia, giving rise to the Kingdom of Sophene. The kingdom was ruled by a branch of the Armenian royal dynasty of Orontids.
The kingdom's capital was Carcathiocerta, identified as the now abandoned town-site of Egil on the Tigris river north of Diyarbakir. However, its largest settlement and only true city was Arsamosata, located further to the north. Arsamosata was founded in the 3rd century B.C. and survived in a contracted state until perhaps the early 13th century A.D. Though the kingdom's rulers were Armenian, the ethnicity of the kingdom was mixed, having a population of Armenian descent and a population of Semitic descent, infiltrating from the South, a situation still existent at the time of the Crusades.