A display device includes a substrate; a pixel connected to a gate line and a data line on the substrate; a connection unit connected to one of the gate line and the data line of the substrate; and a driving integrated circuit mounted on the connection unit. The connection unit includes: a lead line connected to the driving integrated circuit; and at least one first dummy line adjacent to a first side of the connection unit intersecting a side of the substrate, the first dummy line not connected to any line of the connection unit including the driving integrated circuit and the lead line.