The father, in his forties, was convicted of murder, attempted murder, and aggravated arson by the Södertörn District Court on Friday, reported the Expressen newspaper. He was found guilty of setting fire to a cabin in the Stockholm archipelago during a family holiday in September, killing two of his children.
His third child, a seven-year-old girl, managed to escape and alert authorities, but the two sons died from smoke inhalation.
The man admitted in October that he set the house on fire with the intention of killing the three children. He torched the cabin during the night when the children were asleep.
Prosecutors said that the motive behind the fatal attacks was revenge against the children's mother, who had left him.
"Revenge is sweet, you bloody idiot," the man wrote in an SMS sent to his ex-partner on the night of the fire.
The father was arrested the day after the fire on the island of Öland after a huge manhunt including swat teams and police helicopters.
Dalarö, where the cabin was torched, lies in the Haninge municipality in southern Stockholm and is a popular summer holiday destination for Stockholm residents with a large number of wooden holiday homes on the 168-hectare island.