Winifred Marjorie Wagner (née Williams; 23 June 1897 – 5 March 1980) was the English-born wife of Siegfried Wagner, the son of Richard Wagner. She ran the Bayreuth Festival after her husband's death in 1930 until the end of World War II in 1945. She was a friend and supporter of Adolf Hitler, himself a Wagner enthusiast, and she and Hitler maintained a regular correspondence.