Martha Dix (née Lindner; other married name Koch; July 19, 1895, Cologne – March 6, 1985, Sarrians, France) was a German goldsmith and silversmith, as well as the wife of the painter Otto Dix. She was portrayed many times by her husband from 1921 to 1933.[1][2] A well-known double portrait of the couple appears in the photographer August Sander's portfolio People of the 20th Century (1925).