Folio may refer to:

• Bookbinding, meaning
  • A sheet of paper, parchment, or other material folded in half to make two leaves in a codex.
  • A sheet of paper, parchment, or other material used as a single leaf in a codex.
  • Loosely, the page number marked on the page (which may be different from the page count).
• Book size, or Paper size, where folio is a book bound from folio sheets, usually 15" tall or more.
• Book, referring to an unusually large and noteworthy book edition, such as the First Folio of William Shakespeare.
• Folio Society, Publishers of fine illustrated books.
• Folio Weekly, a newspaper published in Florida and Georgia.