William Paul Petersen (born September 23, 1945) is an American actor, singer, novelist, and activist.

Petersen first rose to prominence in the 1950s playing Jeff Stone on The Donna Reed Show, and transitioned to a singing career in the 1960s. In the early 1980s, he had a recurring role as a police officer on Matt Houston, and in the late 1990s, he played the author Paul Conway in the film, Mommy's Day.