A touch sensor includes a base, first sensing electrode columns (FSECs), and second sensing electrode columns (SSECs). The base includes a sensing region (SR) including a rounded corner (RC), and a non-SR outside the SR. The FSECs extend in a direction on the base, each FSEC among the FSECs including first sensing electrodes (FSEs), each FSE among the FSEs including sub-electrodes. The SSECs are alternately disposed with the FSECs on the base, each SSEC among the SSECs including second sensing electrodes (SSEs). Sub-electrodes of one of adjacent FSEs among the FSEs are electrically connected to respective sub-electrodes of another of the adjacent FSEs. A sub-electrode closest to the RC among the sub-electrodes includes a rounded edge (RE) corresponding to the RC. A SSE closest to the RC among the SSEs includes a RE corresponding to the RC, and a protrusion part protruding toward the sub-electrode including the RE.