Following the aftermath of World War II, the UNCLOS treaty, the decolonisation of Cyprus, and the addition of the Dodecanese to Greece's territory have strained the relationship.

Several issues frequently affect their current relations, including territorial disputes over the sea and air, minority rights, and Turkey's relationship with the European Union (EU) and its member states—especially Cyprus.

Greek-Turkish feuding was not a significant factor in international relations from 1930 to 1955, and during the Cold War, domestic and bipolar politics limited competitive behaviour against each other.

[12] In 1853, a Greek embassy was opened in Istanbul; this was discontinued during periods of crisis and eventually transferred to the new capital Ankara in 1923 when the Republic of Turkey was formed.

By the end of the Second Balkan War due to the Treaty of Bucharest (1913) Greece grew by two-thirds; it went from 64,790 to 108,610 km2 (25,020 to 41,930 sq mi) and its population from 2,660,000 to 4,363,000.

Mustafa Kemal united the protesting voices in Anatolia and began a nationalist movement to repel the Allied armies that had occupied the Ottoman Empire and establish new borders for a sovereign Turkish nation.

[49][50] Driven by Eleftherios Venizelos in co-operation with Mustafa Kemal Atatürk, as well as İsmet İnönü's government, a series of treaties between Greece and Turkey were signed in 1930, in effect restoring Greek-Turkish relations and establishing a de facto alliance between the two countries.

[51] The Balkan Pact of 1934 was signed, in which Greece and Turkey joined Yugoslavia and Romania in a treaty of mutual assistance, and settled outstanding issues.

[52] Greece was a signatory to a 1936 agreement that gives Turkey control over the Bosporus and Dardanelles Straits, and regulates the transit of naval warships.

The nations signed the 1938 Salonika Agreement which abandoned the demilitarised zones along the Turkish border with Greece that were a result of the Treaty of Lausanne.

Using the vessel SS Kurtuluş, foodstuffs were collected by a nationwide campaign of Kızılay, the Turkish Red Crescent, and the operation was funded by the American Greek War Relief Association and the Hellenic Union of Constantinopolitans.

In 1941 in anticipation of the Second World War, in the Twenty Classes, adult male Armenians, Greeks and Jews were conscripted into labour battalions.

The tax's main purpose, however, was to nationalise the Turkish economy by reducing minority populations' influence and control over the country's trade, finance, and industries.

[82] In retaliation, in Istanbul, thousands of shops, houses, churches and graves belonging to members of the ethnic Greek minority were destroyed within a few hours, over 12 people were killed and many more injured.

[84][85] Pressure over the resulting London Conference to discuss Cyprus, and to direct attention away from the domestic political problems were the likely motivation of the Turkish Menderes government.

[89] A 1971 Turkish law nationalised religious high schools and closed the Halki seminary on Istanbul's Heybeli Island, an issue that affects 21st-century relations.

[96] Greece formed a defence co-operation agreement with Syria, and between 1995 and 1998 established good relations with Turkey's other neighbours Iran and Armenia.

[100] In 1995, relations began to change with the Greek election of Kostas Simitis who redefined priorities but it wasn't until the meeting of the foreign ministers the following years that this was noticed.

[109] They included agreements on fighting organised crime, reducing military spending, preventing illegal immigration, and clearing land mines on the border.

[113] The conflict between Turkey and Greece is largely over whether the Greek islands are allowed an exclusive economic zone, the basis of claiming rights over the sea.

[117] Islands and islets Iying within three miles (4.8 km) of the coast were included as part of the respective state under the Treaty of Lausanne.

[118] Greece controversially extended this limit to six miles (9.7 km) in 1936, which Turkey did not dispute due to good relations and reciprocated in 1964.

[139] Kemalism evolved to an alternative identity of European orientation as Turkey became a regional centre in the emerging Eurasian political formation.

[142] Negotiations on the division on the island in the 1990s failed because of the Turkish side's recognition of North Cyprus as an independent state, an issue that remains as of 2022.

Gas drilling on territory disputed with Greece using research vessel RV MTA Oruç Reis led to EU sanctions against Turkey.

[147][148][149][excessive citations] The 2010 discovery of natural gas deposits in the eastern Mediterranean, first by Israel and then Egypt, has increased tensions between Greece and Turkey.

[151] The 2016 Turkey-Israel reconciliation led to Greece sabotaging the 2017 Cyprus–UN talks to reunify the island, preventing Israel and Turkey from developing a gas pipeline.

[152] The Caspian Sea is one of the oldest oil-producing regions; it is estimated to have reserves of 48 billion barrels,[153] and 292 trillion cubic feet of natural gas.

In May 2022, Greece signed a deal with Turkey's rival the United Arab Emirates for the distribution of the UAE's liquefied natural gas.

[161][162] Examples of minority mistreatment include: The election of Muftis in Greece and the reopening of the Halki Seminary in Turkey have become the most prominent issues.