Franz Bibfeldt is a fictitious German theologian and in-joke among American academic theologians.
Bibfeldt made his first appearance as the author of an invented footnote in a term paper of a Concordia Seminary student, Robert Howard Clausen. Clausen's classmate, Martin Marty, adopted the name for continued satire and Bibfeldt became a running joke for Martin and his friends. His birthdate and baptismal day was set as November 1, 1897. In 1951, Marty's review of Bibfeldt's The Relieved Paradox was published in the Concordia Seminarian. When the ruse was uncovered, Marty's fellowship to study overseas was revoked, and he instead enrolled in the University of Chicago, where he spent the rest of his academic career.