William Vennard (31 January 1909 Normal, Illinois–10 January 1971 Los Angeles, California) was a famous American vocal pedagogist who devoted his life to researching the human voice and its use in singing.

He was one of the driving forces behind a major shift within the field of vocal pedagogy during the middle of the 20th century. Along with a few other American singing teachers, such as Ralph Appelman at Indiana University, Vennard introduced contemporary scientific research in the areas of human anatomy and physiology into the study of singing. This shift in approach led to the rejection of many of the beliefs and practices held since the bel canto era, most particularly in the areas of vocal registration and vocal resonation.

Vennard was renowned as an excellent teacher whose written works have influenced generations of singers, vocal pedagogues and voice scientists. He taught many successful singers including acclaimed mezzo-soprano Marilyn Horne, who studied under him at the University of Southern California.