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 a first dummy line adjacent to a first side of the connection unit, the first side intersecting a side of the substrate, the first side extending in a first direction, the first dummy line extending in a second direction intersecting the first direction. The side of the substrate overlaps the connection unit, and a third side of the connection unit overlaps the substrate without intersecting the side of the substrate, the third side extending in the second direction. The first dummy line is disposed between the side of the substrate and the third side of the connection unit.