A flexible cable may include: a flexible substrate having a first surface and a second surface that are on opposite sides of the flexible substrate; a first conductive line formed on the first surface of the flexible substrate, and structured to transmit a signal having a first frequency; a second conductive line formed on the first surface of the flexible substrate, and structured to transmit a signal having a second frequency lower than the first frequency; and a ground line formed on the second surface of the flexible substrate, and comprising a first region overlapping the first conductive line and a second region overlapping the second conductive line. The first and second regions may have different shapes.