The Aegean dispute is a set of interrelated controversial issues between Greece and Turkey over sovereignty and related rights in the area of the Aegean Sea. This set of conflicts has had a large effect on Greek-Turkish relations since the 1970s. It has twice led to crises coming close to the outbreak of military hostilities, in 1987 and in early 1996. The issues in the Aegean fall into several categories:

Since 1998, the two countries have been coming closer to overcome the tensions through a series of diplomatic measures, particularly with a view to easing Turkey's accession to the European Union. However, as of 2010, differences over suitable diplomatic paths to a substantial solution are still unresolved.

See also: Foreign relations of Turkey, Foreign relations of Greece

Several of the Aegean issues deal with the delimitation of both countries' zones of influence in the air and on the sea around their respective territories. These issues owe their virulence to a geographical peculiarity of the Aegean sea and its territories. While the mainland coasts of Greece and Turkey bordering the Aegean Sea on both sides represent roughly equal shares of its total coastline, the overwhelming number of the many Aegean islands belong to Greece. In particular, there is a chain of Greek islands lined up along the Turkish west coast (Lesbos, Chios, Samos, and the Dodecanese islands), partly in very close proximity to the mainland. Their existence blocks Turkey from extending any of its zones of influence beyond a few nautical miles off its coastline. As the breadth of maritime and areal zones of influence, such as the territorial waters and national airspace, are measured from the nearest territory of the state in question, including its islands, any possible extension of such zones would necessarily benefit Greece much more than Turkey proportionally.