Cadmus may have a number of meanings:
- Cadmus, in Greek mythology the son of the Phoenician king of Tyre and brother of Europa
- Cadmus, a city in Syria, more often transliterated as Qadmus today
- Mount Cadmus, a mountain in Asia Minor
- Project Cadmus, a fictional government organization in DC Comics
- Cadmus (journal), an economic/humanitarian journal.
- Cadmus of Miletus, a 6th century BC logographer
- Cadmus of Kos, tyrant of Zancle, son of Scythes
- Paul Cadmus, an American artist
- Cadmus, a German Unix minicomputer brand in 1980s and 1990s build by Periphere Computer-Systeme
- HMS Cadmus, five ships of the Royal Navy