The Craiova Group (Quadrilateral), Craiova Four, or C4 is a cooperation project of four European states – Romania, Bulgaria, Greece and Serbia – for the purposes of furthering their European integration as well as economic, transport and energy cooperation with one another.

The Group originated in a summit meeting of the heads of governments of Bulgaria, Romania and Serbia, held on 24 April 2015 in the Romanian city of Craiova.

[5][6][7][8][9][10][11][12] One of the first initiatives, after a meeting in Vidin, Bulgaria, was to strengthen the telecommunication networks in the border areas of the countries.

[13] Other goals include helping Serbia join the European Union and the construction of a motorway linking Bucharest, Sofia and Belgrade.

[3] On 2 November 2018, Prime Minister of Bulgaria Boyko Borisov stated that Prime Minister of Greece Alexis Tsipras proposed joint bid for the 2030 FIFA World Cup by Bulgaria, Romania, Serbia and Greece during the meeting in Thessaloniki.