Silphium is an unidentified plant recorded in classical antiquity, believed extinct.
Silphium or Silphion can also refer to:
Silphium (genus) of North American daisies in the family Asteraceae known as "rosinweeds" Silphion (insect), an extinct protorthopteran insect genus in the family Anthracothremmidae
See also Silpium, a mountain in Greek mythology