A touch sensor may include a sensing area and a non-sensing area. The touch sensor may include: a sensor base layer; a first sensing electrode and a second sensing electrode each disposed on the sensor base layer in the sensing area; a first sensing line and a second sensing line each disposed on the sensor base layer, the first sensing line being electrically connected to the first sensing electrode, the second sensing line being electrically connected to the second sensing electrode; and an auxiliary line disposed on the sensor base layer. The second sensing line may include a 2-1-th sensing line disposed in the sensing area, and a 2-2-th sensing line disposed in the non-sensing area. The auxiliary line may overlap the second sensing electrode in a plan view, enclose at least a portion of the 2-1-th sensing line, and be electrically connected to the second sensing electrode.