William Joseph Schallert (July 6, 1922 – May 8, 2016) was an American character actor who appeared in dozens of television shows and films over a career spanning more than 60 years. He is known for his roles on Richard Diamond, Private Detective (1957–1959), Death Valley Days (1955–1962), and The Patty Duke Show (1963–1966).

Schallert was born in Los Angeles, California, the son of Edwin Francis Schallert, a longtime drama critic for the Los Angeles Times, and Elza Emily Schallert (née Baumgarten), a magazine writer and radio host. He began acting while a student at the University of California, Los Angeles (UCLA) but left to become an Army Air Corps fighter pilot in World War II. He returned to UCLA after the war and graduated in 1946.

After graduating from UCLA, Schallert began his acting career in the theater. He appeared in several productions at the Circle Theatre in Los Angeles, including a staging of W. Somerset Maugham's Rain in 1948, which was directed by Charlie Chaplin.

Schallert made his television debut in 1951, and he quickly became a familiar face on the small screen. He appeared in numerous guest roles on shows such as The Adventures of Superman, The Twilight Zone, and The Dick Van Dyke Show. He also had recurring roles on The Patty Duke Show, The Nancy Drew Mysteries, and The Torkelsons.

In addition to his work on television, Schallert also appeared in several films, including The Bridges of Toko-Ri (1954), The Apartment (1960), and The Sting (1973).

Schallert died in Pacific Palisades, California, in 2016, at the age of 93. He was survived by his wife, Leah Waggner, and their four children.