A touch substrate includes a base substrate, a first sensing element and a first variable voltage part. The first sensing element senses a first light and includes a first active pattern disposed on the base substrate, a first sensing source electrode disposed on the first active pattern, a first sensing drain electrodes disposed on the first active pattern and spaced apart from the first sensing source electrode, and a first sensing gate electrode disposed on the first sensing source electrode and the first sensing drain electrode. The first variable part provides at least one of a first sensing gate voltage and a second sensing gate voltage to the first sensing gate electrode based on reception of the first light, where a level of the second sensing gate voltage is higher than a level of the first sensing gate voltage.