William James Porter (September 1, 1914 – March 15, 1988) was a British-American diplomat who from 1971 to 1973 headed the U.S. delegation to the Paris Peace Talks to end the Vietnam War.

William J. Porter was born in Stalybridge, England on September 1, 1914, the son of a Royal Navy officer who died during World War I.

While serving in Syria, he met and married Eleanore Henry, a United States Army nurse from Philadelphia, who was posted in Cairo.

He showed such skill in handling both French and Algerian officials that United States Ambassador to South Vietnam Henry Cabot Lodge Jr. asked that Porter be assigned to Saigon.

In 1971, President Richard Nixon selected Porter to replace David K. E. Bruce as head of the U.S. delegation at the Paris Peace Talks.