Vaso (Vasily) Ivanovich Abaev (Ossetic: Абайты Иваны фырт Васо, Russian: Василий Иванович Абаев, also transilterated as Abaity and Abayev) (15 December 1900 – 18 March 2001) was an ethnically Ossetian Soviet linguist specializing in Ossetian and Iranian linguistics. He was born in Kobi, Georgia, Russian Empire.
Abaev studied at the Gymnasium of Tiflis in 1910-1918 and graduated from the Leningrad University in 1925. He studied Iranian philology under Friedman's direction and, as many other young linguists, fell under the influence of the controversial Nicholas Marr, joining Marr's Yaphetic Institute in 1928. After Marr's death, he moved to broad Iranian topics and field work in Ossetia until the end of the World War II. In 1945 he moved back to Leningrad where he published his work on the Nart sagas, a dictionary and grammar book of Ossetian. With Stalin's condemnation of Marr's linguistic theories the Yaphetic Institute was purged, but Abaev was spared.
Starting with the 1950s, Abayev became internationally famous as the leading authority on Scythian and Sarmatian linguistics. Assisted by his friend, Georges Dumézil, Abaev demonstrated connections between the Scythian languages and modern Ossetian. He also pointed out some striking similarities between Ossetian and Celtic mythology. His magnum opus, the Etymological Dictionary of Ossetian Language, was published in four volumes between 1959 and 1989. He died at the age of 100 in Saint Petersburg. Several years later, a monument to him was unveiled in Tskhinvali.