In 1922, Ziegler married Maria Kurtz. They had two children, Erhart and Marianna. His daughter, Dr. Marianna Ziegler Witte was a doctor of medicine and married a chief physical of a children's hospital (at that time) in the Ruhr. His son, Dr. Erhart Ziegler, became a physicist and patent attorney. In addition to his children, Karl Ziegler has five grandchildren by his daughter, and five by his son. At least one of his grandchildren, Cordula Witte, attended his Nobel Prize reception as there is a picture of the two of them happily dancing. Ziegler enjoyed traveling around the world with his family, especially on cruises. He even charted special cruises and airplanes for eclipse viewing. It was during a 1972 eclipse-viewing cruise with his grandson that Karl Ziegler became ill. He died a year later.