Flannel is a soft 2/2 twill woven fabric, of various fineness. It usually doesn't have a nap, and instead gains its softness through the loosely spun yarn it is woven from. It is commonly used to make clothing, bed sheets, and sleepwear.

Flannel was originally made from carded wool or worsted yarn, but is now often made from either wool and cotton, or wool and synthetic fibre.