Glücksburg (German pronunciation: [ˈɡlʏksˌbʊʁk] ; Danish: Lyksborg) is a small town northeast of Flensburg in the district of Schleswig-Flensburg, in Schleswig-Holstein, Germany.
It is situated on the south side of the Flensborg Fjord, an inlet of the Baltic Sea, approx. 10 km northeast of Flensburg. The town was originally the home of the family Schleswig-Holstein-Sonderburg-Glücksburg (or simply Glücksburg), members of which have reigned in the past in Greece and several northern German states. Members of the family still reign in Denmark and Norway since 1863 and 1905 respectively, and have reigned in the United Kingdom and the 14 other Commonwealth realms since the accession of Charles III in 2022.