They were the driver and passenger in a car that collided with another car near the village of Killygordon on the main road between Lifford and Ballybofey at around 3.45pm.
One of the men who died was a 39-year-old married man from Lithuania. He had two children and had been living in the Ballybofey area.
The other man who died was a 31-year-old single man from Russia who had also been living in the area.
A man and woman in the second car have been taken to Letterkenny General Hospital.
The woman is in a critical condition and her husband is stable. They are both in their 50s.
The main road between Lifford and Ballybofey will remain closed until tomorrow morning.
Earlier, a teenager died in a road crash in Connemara, Co Galway.
The 16-year-old was a passenger in a car that went off the road near Leitir Móir at around 10.30pm last night.
The driver of the car, also a teenager, was taken to Galway University Hospital with minor injuries.
The collision occurred at Crimnagh village on the only road leading to the islands.
