Karl Waldemar Ziegler (November 26, 1898–August 12, 1973) was a German chemist who won the Nobel Prize in Chemistry in 1963, with Giulio Natta, for work on polymers. One of many awards Ziegler received was the Werner von Siemens Ring in 1960 jointly with Otto Bayer and Walter Reppe, for expanding the scientific knowledge of and the technical development of new synthetic materials.

He received his Ph.D. in 1920, studying under Karl von Auwers. His dissertation was on "Studies on semibenzole and related links" which lead to three publications. He progressed through schooling quickly receiving a doctorate from the University of Marburg in 1920.
In 1926 he became a professor at the University of Heidelberg where he spent the next ten years researching new advances in organic chemistry.
In 1933 Zielger published his first major work on large ring systems, “Vielgliedrige Ringsysteme” which presented the fundamentals for the Ruggli-Ziegler dilution principle.
In 1936 he became Professor and Director of the Chemical Institute (Chemisches Institut) at the University of Halle/Saale and was also a visiting lecturer at the University of Chicago.
From 1943 until 1969, Ziegler was the Director of the Max Plank Institute for Coal Research (Max-Planck-Institut fur Kohlenforschung) formerly known as the Kaiser-Wilhelm Institute for Coal Research (Kaiser-Wilhelm-Institut fur Kohlenforschung) in Mülheim an der Ruhr as a successor to Franz Fischer.
He was also the president of the German Society for Petroleum Science and Coal Chemistry (Deutsche Gesellschaft für Mineralölwissenschaft und Kohlechemie), which was from 1954 to 1957.
Karl Ziegler died in Mülheim, Germany August 12, 1973.