Twine is a strong thread, light string or cord composed of two or more thinner strands twisted, and then twisted together (plied). The strands are plied in the opposite direction to that of their twist, which adds torsional strength to the cord and keeps it from unravelling. This process is sometimes called reverse wrap. The same technique used for making twine is also used to make thread, which is thinner, yarn, and rope, which is stronger and thicker, generally with three or more strands.

Natural fibres used for making twine include wool, cotton, sisal, jute, hemp, henequen, paper, and coir. A variety of synthetic fibres are also used. Twine is a popular substance used in modern-day crafting.