A display device includes a substrate including a display area and a non-display area disposed near the display area, a plurality of pixels disposed in the display area, a plurality of signal lines disposed on the substrate and connected to the pixels, and a pad portion disposed in the non-display area and including a plurality of pads. The signal lines include a first crack detecting line connected to a first test voltage pad and a first pad at a first node, connected to a second pad at a second node, and extending around the non-display area between the first node and the second node, as well as a first data line including a first end connected to a first transistor connected to the first crack detecting line at the second node, and a second end connected to corresponding pixels from among the plurality of pixels.