David Oliver Cauldwell (June 17, 1897 – August 30, 1959) was a prolific and pioneering sexologist, who coined the term transsexual as used in its current definition.
Many of his monographs on sex, psychology, or health were published by Emanuel Haldeman-Julius in such forms as Big Blue Books.
He was the editor of Sexology magazine's question and answer department.
Cauldwell and Harry Benjamin were "two early and important American voices on transsexuality".