A display device includes a substrate including a display area and a non-display area disposed at a peripheral area of the display area. A plurality of pixels is disposed in the display area of the substrate. A plurality of signal lines is disposed on the substrate and is connected to the plurality of pixels. The plurality of signal lines include a plurality of gate lines and a plurality of data lines disposed on the substrate. A crack detecting line is disposed in the non-display area and is connected to a first data line of the plurality of data lines. The crack detecting line includes a first portion disposed below an insulating layer and a second portion disposed above the insulating layer. The first portion and the second portion are connected with each other through a contact hole formed in the insulating layer.