Interlining Is a layer of fabric sewn in or fused between the face and the lining of a garment. Interlining materials can be woven, knitted, or created by fusing fibers together. Garments with interlining tend to be stronger, because of the added layer of fabric support. In addition, they drape better, while keeping the wearer's temperature relatively stable. Interlining generally indicates a higher level of quality in a garment, because of the additional manufacturing time involved.