Princess Barbara of Prussia (German: Prinzessin Barbara von Preußen; 2 August 1920 – 31 May 1994) was the only daughter and elder child of Prince Sigismund of Prussia and Princess Charlotte of Saxe-Altenburg. She was a great-granddaughter of Frederick III, German Emperor and a great-great-granddaughter of Queen Victoria. On 17 September 1952 she was legally adopted by her paternal grandmother, Princess Irene of Prussia (née Princess Irene of Hesse and by Rhine), a granddaughter of Queen Victoria.

On 5 July 1954 in Glücksburg Barbara wed civilly Duke Christian Louis of Mecklenburg-Schwerin, second son of Frederick Francis IV, Grand Duke of Mecklenburg-Schwerin. They married in a religious ceremony on 11 July 1954. Duke Christian had been held as a prisoner-of-war for eight years before being finally released by the Russians in 1953. Despite the fact that Barbara was thirty-four and the groom was forty-two, it was the first marriage for both of them. The 11 July ceremony was held at Glücksburg Castle, and was attended by 130 representatives of Germany's royal and noble families. Among them was Louis Ferdinand, Prince of Prussia, the head of the House of Hohenzollern.

They had two daughters:

Her daughters are the only remaining senior members of the House of Mecklenburg-Schwerin. After the death of her brother-in-law in 2001, the male line of the House of Mecklenburg-Schwerin became extinct.

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