As of the 2011 census, the population of the town is 12,894.
During the medieval period, Martuni was known as Mets Kznut, but from 1830-1922 it was called Nerkin Gharanlugh and in 1926 it was changed to Martuni in honor of the first Soviet premier of Armenia, Aleksandr Myasnikyan, whose nom de guerre was "Martuni". Martuni was the former capital of Gegharkunik Province. Martuni has a church called Astvatsatsin church which was rebuilt in 1886. There is also an Iron Age fort excavated in 1997 by an Armenian-Italian team.