The national Flag of Denmark, the Dannebrog, is red with a white Scandinavian cross that extends to the edges of the flag; the vertical part of the cross is shifted to the hoist side. The cross design of the Danish flag was subsequently adopted by the other Nordic countries: Sweden, Norway, Finland, and Iceland. During the Danish-Norwegian personal union, the Dannebrog was also the flag of Norway and continued to be, with slight modifications, until Norway adopted its current flag in 1821.

The Dannebrog is the oldest state flag in the world still in use, with the earliest undisputed source dating back to the 14th century. Prior to the use of the Dannebrog, Danish forces were known to have used the raven banner.