The 27-year-old man was jailed for life after a court found him guilty of 20 charges of "murder as a terror offence."
A Syrian asylum seeker in Austria has been jailed for life for murdering 20 wounded soldiers loyal to regime leader Bashar al Assad.
The man was fighting alongside an anti-Assad militia near the city of Homs, a court spokesman said.
The man was arrested in June 2016 at a refugee shelter in the Austrian state of Tyrol.
The court in the city of Innsbruck announced its sentence on Wednesday after a jury found the 27-year-old guilty of 20 charges of "murder as a terror offence."
An interpreter told the court the man had boasted of belonging to an opposition group and shooting unarmed or injured Assad troops.
After his arrest, the man initially admitted to the 2013-2014 killings in the western Syria region of Homs. He later retracted his confession, saying his testimony had been badly translated.
The man, who was not named, was tried for war crimes under Austrian law. His lawyer said he would appeal against the ruling.
Austria has jailed several people for belonging to terrorist organisations, a charge usually leveled against foreign or local militants fighting in Syria alongside Daesh.
However, Austrian authorities could not extradite him to face charges in Syria because of the civil war, now in its seventh year, pitting Assad against a range of terrorist and opposition groups.