Mohammed Reza Heydari resigned as consul of the Iranian Embassy and went into hiding along with his family after a December crackdown by Tehran on protesters disputing the results of last year's presidential election.
Eight people were killed in the clashes between security forces and opposition backers in the most serious bloodshed since the aftermath of the June vote, when dozens died.
Heydari is believed to be the first Iranian diplomat to resign in protest against the government's moves.
"He and his family have been granted political asylum in Norway," said Bente Engesland, spokeswoman for the Norwegian Immigration Directorate (UDI).
She said UDI's decisions regarding political asylum were based on a number of factors, including whether the asylum seeker would be safe if returned to his home country. Heydari had said he "feared for his life" after resigning.
Iran's Foreign Ministry has dismissed Heydari's resignation announcement, saying his posting simply ended.
Heydari told Reuters last month that he expected other disgruntled Iranian diplomats to follow his example in the coming weeks and months, which could signal deep divisions within the Iranian establishment over the country's future.
Anti-government demonstrators say the election was rigged to secure President Mahmoud Ahmadinejad's re-election. The authorities deny the accusations, which they say were part of a Western-orchestrated plot to overthrow the government.
