Darning is a sewing technique for repairing holes or worn areas in fabric or knitting using needle and thread alone. It is often done by hand, but it is also possible to darn with a sewing machine. Hand darning employs the darning stitch, a simple running stitch in which the thread is "woven" in rows along the grain of the fabric, with the stitcher reversing direction at the end of each row, and then filling in the framework thus created, as if weaving. Darning is a traditional method for repairing fabric damage or holes that do not run along a seam, and where patching is impractical or would create discomfort for the wearer, such as on the heel of a sock.

Darning also refers to any of several needlework techniques that are worked using darning stitches:

• Pattern darning is a type of embroidery that uses parallel rows of straight stitches of different lengths to create a geometric design.
• Net darning, also called filet lace, is a 19th-century technique using stitching on a mesh foundation fabric to imitate lace.
• Needle weaving is a drawn thread work embroidery technique that involves darning patterns into barelaid warp or weft thread.