In ancient Greek costume, a tainia (Ancient Greek: ταινία; pl.: ταινίαι or Latin: taenia; pl.: taeniae) was a headband, ribbon, or fillet.

The tainia headband was worn with the traditional ancient Greek costume. The headbands were worn at Greek festivals.^[1] The gods also bound their heads with tainiai.^[2] Furthermore, cult images,^[3] trees,^[4] urns, monuments, animal sacrifices and the deceased^[5] had tainiai wound around them. They were later adopted by the Romans.^[6] A similar type of headband was the diadema, used as a symbol for kings.