A touch sensor includes sensing electrodes and a touch controller. The sensing electrodes are electrically separated from each other, the sensing electrodes including a first sensing electrode and a second sensing electrode. The touch controller is configured to provide driving signals to the sensing electrodes, to receive sensing signals from the sensing electrodes, and to determine a touch position based on the sensing signals. The touch controller is further configured to, in response to reception of a frequency increase signal including information about the first sensing electrode, set a frequency of a driving signal provided to the first sensing electrode as a first frequency, and to set a frequency of a driving signal provided to the second sensing electrode as a second frequency different than the first frequency.