Afon Llynfi may refer to:

• Afon Llynfi (Wye), the tributary of the River Wye at Llangors
• River Llynfi, the tributary of the Ogmore River near Maesteg

• Signum crucis
• Signum (disambiguation)
• Signum Magnum
• Signus loop
• Sign value
• Sign Wave
• Sign waver
• Signwriter
• Sign Writing
• SignWriting script
• Signy-avenex
• Signy Avenex
• Signy-Avenex, Switzerland
• Signy Fardal
• Signy-l'Abbaye
• Signy-le-Petit
• Signy-Montlibert
• Sign Your Name
• Sign your name
• Sign your posts
• Signy Station
• Signé Charlotte
• Signéville
• Sign “☮” the Times Tour
• Sign '☮' the Times