Greek Foreign Minister Nikos Kotzias quit his post on Wednesday, the government said, in a cabinet dispute over the country's controversial name deal with Macedonia.
"Prime Minister Alexis Tsipras has accepted the foreign minister's resignation," the PM's office said in a statement, adding that Tsipras himself would take over the post.
Kotzias on Tuesday had clashed in a cabinet meeting with Defence Minister Panos Kammenos, who is also the coalition partner holding up Tsipras' government.
Head of the nationalist Independent Greeks party, Kammenos has threatened to defect from the government in opposition to the deal brokered by Kotzias and Tsipras earlier this year to rename Greece's neighbour North Macedonia.
The deal has raised strong objections in both countries.
Greece also has a northern province named Macedonia, the heart of Alexander the Great's ancient kingdom.
Many Greeks fear the deal on the table will officially enable Skopje to lay claim to their cultural heritage.