Glücksburg (Danish:Lyksborg) is a small town in the district 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), since 1863 the royal family of Denmark and since 1905 of Norway. A branch of the family was the former royal family of Greece, which includes Prince Philip, Duke of Edinburgh. His descendants, including Charles, Prince of Wales, Prince William, Duke of Cambridge, and Prince George of Cambridge, are members of the House of Windsor under British law, but genealogically are members of a cadet branch of the House of Glücksburg.