The use of the country name "Macedonia" was disputed between Greece and the Republic of Macedonia between 1991 and 2019. The dispute was a source of instability in the Western Balkans for 25 years. It was resolved through negotiations between the two countries, mediated by the United Nations, resulting in the Prespa Agreement, which was signed on 17 June 2018. Pertinent to its background is an early 20th-century multifaceted dispute and armed conflict that formed part of the background to the Balkan Wars. The specific naming dispute, although an existing issue in Yugoslav–Greek relations since World War II, was reignited after the breakup of Yugoslavia and the newly-gained independence of the former Socialist Republic of Macedonia in 1991. Since then, it was an ongoing issue in bilateral and international relations until it was settled with the Prespa agreement in June 2018, the subsequent ratification by the Macedonian and Greek parliaments in late 2018 and early 2019 respectively, and the official renaming of Macedonia to North Macedonia in February 2019.

The name Macedonia is used in a number of competing or overlapping meanings to describe geographical, political and historical areas, languages and peoples in a part of south-eastern Europe. It has been a major source of political controversy since the early 20th century. The situation is complicated because different ethnic groups use different terminology for the same entity, or the same terminology for different entities, with different political connotations.