Antoinette Roberte Sophie Wilhelmine (7 October 1899 – 31 July 1954), commonly referred to as Antonia, was the last Crown Princess of Bavaria before World War II.

By birth, she was a member of the Luxembourgish House of Nassau-Weilburg as the child of Guillaume IV, Grand Duke of Luxembourg and Infanta Marie Anne of Portugal.

Born at Schloss Hohenburg,[citation needed] at Lenggries in Upper Bavaria, Antonia was the fourth daughter of Guillaume IV, Grand Duke of Luxembourg, who reigned between 1905 and 1912, and Marie Anne, a princess of the Portuguese House of Braganza.

This led to criticism of the close ties between the Luxembourgish Grand Ducal Family and the royalty of the German Empire at a time when Luxembourg was occupied by Germany.

[2] Despite the abdication of her elder sister, and the overthrow of the Kingdom of Bavaria in favour of a republic, the two were married on 7 April 1921 at Schloss Hohenburg.

A meeting with the British Foreign Office's summary reports Rupprecht as telling George V that he "remained convinced that the Fuhrer was insane.