The widow of ex-King Zog was being treated for a lung disease in a military hospital in the capital, Tirana.
She subsequently suffered at least three heart attacks, the last of which was fatal, a hospital spokesman said.
The Hungarian-born countess, Geraldine Nagy-Appony, was married in 1938 to King Zog, a Muslim chieftain who proclaimed himself monarch in 1928.
They left the country together with their infant son Leka in April 1939, when fascist Italy invaded the country.
The monarchy was subsequently abolished by Albania's post-war communist leaders, and the royals were refused permission to return home.
Queen Geraldine spent more than 60 years in exile before returning to Albania in July this year, after the law had been changed.
King Zog himself died in exile in Paris in 1961, at the age of 66, having never returned home.
Leka, who had been designated his successor, returned to Albania in 1997, after the fall of the communist regime, in a failed campaign to take the throne.
Two-thirds of Albanian voters rejected the restoration of the monarchy in a referendum held that year.
But he was forced to flee again amid rioting following the referendum.
A court in the capital Tirana later found him guilty in absentia of organising an armed uprising.
A later amnesty allowed him to return again.