The airline, the biggest carrier in Africa, said on Tuesday that it would operate daily flights from the national capital Addis Ababa to the Tigrayan capital of Mekele.
The schedule will increase in frequency depending on demand, it said in a statement.
The announcement comes a day after an Ethiopian delegation made the first high-level government visit to the rebel-held region since the signing of a peace deal last month.
"We are truly pleased with the resumption," Ethiopian Airlines Group CEO Mesfin Tasew said.
"These flights will enable families to reunite, facilitate the restoration of commercial activities, stimulate tourist flow and bring many more opportunities which will serve the society."
Aid has started trickling back into Tigray since the peace deal was signed on November 2, going some way to alleviating chronic shortages of food, fuel, cash and drugs.
But the region of six million is still largely without electricity and phone lines, while internet and banking services have only partly been restored.
Mekele was hooked up to the national electricity grid on December 6, and the country's biggest bank, the Commercial Bank of Ethiopia, announced on December 19 that financial operations had resumed in some towns.
The war began in November 2020 when Prime Minister Abiy Ahmed sent in troops after accusing the Tigray People's Liberation Front (TPLF), the region's ruling party, of attacking army bases.
Estimates of fatalities vary widely, with the United States saying that as many as half a million people have died. More than two million people have been displaced and hundreds of thousands to the brink of famine.
Access to northern Ethiopia is severely restricted and Tigray has been under a communications blackout for more than a year, making it impossible for journalists to independently verify the situation on the ground.