William Hannan Spier (October 16, 1906 – May 30, 1973) was an American writer, producer, and director for television and radio. He is best known for his radio work, notably Suspense and The Adventures of Sam Spade.

Born in New York City, Spier began his career on the editorial staff of Musical America magazine, eventually becoming its chief critic.

He was married to Mary Scanlan and had three children: Peter (deceased), Greta, and Margaret. He was also married to Kay Thompson and then to June Havoc until his death in 1973.