The 15-minute weather system came after two days of soaring temperatures up to 37 degree Celsius in the Mediterranean country.
Six of the people killed were holidaymakers, according to Greek Minister for Citizen Protection Michalis Chryssohoidis.
The body of an unidentified man was also found on a beach.
Gusts of wind reached more than 300 km per hour, accompanied by torrential rain and hail, overturning cars and ripping off roofs, electrical poles and trees.
Two Russians, a 39-year-old man and his son, were hit by a fallen tree in the town of Nea Potidea.
Two Romanians, a 54-year-old woman and her eight-year-old son, died when the roof of a tavern collapsed in Nea Plagia.
A Czech couple were killed when their caravan was overturned by strong wind.
Their son and grandson were also in the vehicle at the time but managed to survive.
A fisherman, 62, has also been missing since Wednesday evening. He left at around 7.30pm in his boat and has not been heard from since then.
Another 108 people were injured, 23 of whom remain hospitalized, including five children and a woman in critical condition, according to government spokesman Stelios Petsas.
Athansios Kaltsas, Director of the Nea Moudania Medical Centre, where many of the injured were treated, said "It is the first time in my 25-year career that I have lived through something like this."
"It was so abrupt, and so sudden," he told Greek television.
He said that more than fifty people, aged between eight months and 70 years, were treated at the center mostly for head injuries or fractures from tree branches or other objects flying through the air.
The fire department said it received more than 600 calls throughout the night.
There were power cuts in the affected area due to high voltage poles being felled by the winds.
A government spokesman said that electricity has been restored in some areas but that full recovery may take until Saturday.
The storm that has affected central, western and northern Greece, causing damage to building with roof tiles and terrace railings ripped off.
It has also destroyed some of the peach and nectarine crops in the country.
Regional authorities have declared a state of alert for the affected areas.