The Treaty of Akhal (Russian: Ахалский договор, Persian: پیمان آخال), also known as Akhal-Khorasan Boundary Convention, was an agreement signed between Qajar Iran and Imperial Russia on 21 September 1881 to mark Iran's official recognition of Khwarazm's (mostly the territory of present-day Turkmenistan) annexation by the Russian Empire.
The title of the treaty is derived from the name of the vast region north of Khorasan where the Turkmen tribe of Tekke lived – Akhal.
The Treaty of Turkmenchay was an agreement between Qajar Iran and the Russian Empire, which concluded the Russo-Persian War (1826–1828). It was second of the series of treaties (the first was the 1813 Treaty of Gulistan and the last, the 1881 Treaty of Akhal) signed between Qajar Iran and Imperial Russia that forced Iran to cede or recognize Russian influence over the territories that formerly were part of Iran.
The treaty was signed on 22 February 1828 (5 Sha'ban 1243) in Torkamanchay (a village between Tabriz and Tehran). It made Iran cede the control of several areas in the South Caucasus to Russia: the Erivan Khanate, the Nakhchivan Khanate and the remainder of the Talysh Khanate. The boundary between Russia and Iran was set at the Aras River. These territories are now Armenia, the south of the Republic of Azerbaijan, Nakhchivan and Iğdır Province (now part of Turkey).