A touch sensor and an organic light-emitting display including the sensor are disclosed. In one embodiment, the touch sensor includes i) a substrate, ii) a sensing unit formed on or over the substrate and containing hydrogen ions, iii) a touch sensor active layer formed on or above the sensing unit and iv) a touch sensor source electrode and a touch sensor drain electrode that are electrically connected to the touch sensor active layer. The touch sensor further includes a protective layer covering the touch sensor source electrode and the touch sensor drain electrode, and an opposite electrode formed on the protective layer, wherein at least part of the opposite electrode is formed substantially directly above the touch sensor active layer.