Altyn (Russian алты́н, also алты́нник altýnnik) is a historical Russian currency (symbol: ). The name in Tatar is altı (алты) meaning "six", since it was worth 6 half-dengas (six halves, Russ. шесть полушек), equivalent to three kopek silver, then copper, a small value coin, or 180–206 copper puls.
From the 15th century, altyn had been in use in several Russian principalities as a Eurasian currency between Russian and Asian traders. They were minted from 1654 under Alexis I, under Peter I as silver coins from 1704 to 1718. Later they were revived under Nicholas I as copper coins with a value of three kopeks from 1839. While the name altyn eventually got lost, three-kopek-coins circulated in Russia until 1991.
In the 2010s, the Eurasian Economic Commission drafted first proposals to revive the altyn once again by 2025 as a common currency of the Eurasian Economic Union, although western sanctions against Russia may cut the process to 3-5 years.