William J. Ziegler Jr. (July 21, 1891 – March 3, 1958) was an American business executive, philanthropist, polo player, yachtsman, and a Thoroughbred racehorse owner and breeder.

[2] He was listed as living at his home on Great Island, Noroton, Connecticut in 1917, when he was treated for appendicitis.

[7] He married his first wife, Gladys in 1912, then lived in the William Ziegler House, a New York City mansion at 2 East 63rd Street they had designed by Frederick Sterner in 1919.

[1] On his death in 1958 at the 55th Street mansion, Helen Keller wrote a tribute about him in the New York Times.

Keller called his death an "irreparable loss" to the American Foundation for the Blind.