The Visegrád Group, Visegrád Four, V4, or European Quartet, is a cultural and political alliance of four countries of Central Europe (Czech Republic, Hungary, Poland and Slovakia), all of which are members of the EU and of NATO, to advance co-operation in military, cultural, economic and energy matters with one another and to further their integration with the EU.The Group traces its origins to the summit meetings of leaders from Czechoslovakia, Hungary and Poland held in the Hungarian castle town of Visegrád on 15 February 1991. Visegrád was chosen as the location for the 1991 meeting as an intentional allusion to the medieval Congress of Visegrád in 1335 between John I of Bohemia, Charles I of Hungary and Casimir III of Poland.

After the dissolution of Czechoslovakia in 1993, the Czech Republic and Slovakia became independent members of the group, thus increasing the number of members from three to four. All four members of the Visegrád Group joined the European Union on 1 May 2004.