Sigard Adolphus Knopf (November 27, 1857 – July 15, 1940) was a German-born American physician. Born Siegmund Knopf on November 27, 1857, he received his early education at the Higher Municipal School in Halle-on-the-Saale before moving to the United States in 1880. After being an instructor in non-English languages in the Los Angeles area he matriculated to the University of Southern California, where he studied during 1884–86. In 1888 he graduated with an M.D. from Bellevue Hospital Medical School, then practiced medicine in Los Angeles for two years. He was married to Perle Nora Dyar in 1889; the couple would have no children. Leaving for France to study at the University of Paris, he received an A.B. and B.S. from the institution in 1891. For the next four years he worked at hospitals