Herbert Julius von Denffer (born 4 June 1907, date of death unknown) was a German actuarial mathematician.
He was born in Narva, Estonia.
During World War II, Dr Herbert Denffer worked as a cryptanalyst in Referat F, the Mathematical Referat, as part of the Inspectorate 7/VI, that was the signals intelligence agency of the Wehrmacht, before and during World War II.
He would later work for the General der Nachrichtenaufklärung, the successor organization to the In 7/VI, specifically undertaking research in general theory of cryptography.