A touch sensor and a touch sensing system including the same. The touch sensor according to an embodiment may include a substrate having a first surface and a second surface opposite the first surface, a plurality of first electrodes on the first surface of the substrate, a plurality of second electrodes on the second surface of the substrate, and a plurality of coupling parts configured to couple the plurality of first electrodes to the plurality of second electrodes, respectively. Each of the first electrodes and the second electrodes has a spirally wound shape.