A torsion spring is a helical spring used to produce torque or store mechanical rotational energy when integrated into an assembly construction. It pushes objects back to their initial position.

The extremities of the torsion spring are fixed to objects that rotate around the central axis of the spring. A torsion spring is typically mounted on a mandrel. Enough space should be left between the mandrel and the inner side of the spring body. If there is too much space, the spring may collapse, too little and the spring may lock onto the mandrel when loaded and distort.

A torsion spring has multiple uses and is frequently used by a number of industrial sectors.