An array substrate of a display device includes an active area with curved corner portions and a compensation unit to reduce a difference in a parasitic capacitance of each gate line and each data line. Also, a plurality of data lines disposed to overlap the corner portions of the active area may be disposed with a different width therebetween to reduce a difference in parasitic capacitance of each gate line or data line disposed to overlap the corner portions of the active area and to reduce a resistance difference between data lines. Therefore, a degree of delay of a signal transferred through a plurality of gate lines or data lines can be similar in each gate line or data line, so that a defect can be prevented in a displayed image.