The Weimar Triangle is a regional alliance of France, Germany, and Poland created in 1991 in the German city of Weimar. The group is intended to promote co-operation between the three countries in cross-border and European issues.

Weimar is a city in the German state of Thuringia, in Central Germany between Erfurt to the west and Jena to the east, 80 km (50 mi) southwest of Leipzig, 170 km (106 mi) north of Nuremberg and 170 km (106 mi) west of Dresden. Together with the neighbouring cities of Erfurt and Jena, it forms the central metropolitan area of Thuringia, with approximately 500,000 inhabitants. The city itself has a population of 65,000. Weimar is well-known because of its cultural heritage and importance in German history.