Oxi Day is celebrated throughout Greece, Cyprus and the Greek communities around the world on October 28 each year. Oxi Day commemorates the rejection by the Greek Prime Minister Ioannis Metaxas of the ultimatum made by Italian dictator Benito Mussolini on 28 October 1940 and the subsequent Hellenic counterattack against the invading Italian forces at the mountains of Pindus during the Greco-Italian War and Greek resistance during the Axis occupation.
In response to Metaxas's refusal, Italian troops stationed in Albania, then an Italian protectorate, attacked the Greek border at 05:30 am – the beginning of Greece's participation in World War II.