The flag of Schleswig-Holstein is a horizontal tricolour of blue, white, and red.

Schleswig-Holstein is one of the 16 states of Germany, comprising most of the historical duchy of Holstein and the southern part of the former Duchy of Schleswig.

[1] After the British Military Government made Schleswig-Holstein a German state in 1946, this flag was first hoisted after some debate on 29 August 1946.

[1] The plain tricolour is the state's civil flag.

[1] The tricolour was previously used for the Prussian province of Schleswig-Holstein (1868-1946).