A display device includes a substrate and a circuit layer. The circuit layer includes pixel drivers; data lines; a first transmission detour line electrically connected to, among the data lines, a first data line and extending in a first direction; and a second transmission detour line adjacent to, among the data lines, a second data line, extending in a second direction, and electrically connected to the first transmission detour line. The first transmission detour line includes a first main stream extending in the first direction between the first data line and the second transmission detour line; a first sub-branch extending in the second direction from the first main stream, and overlapping a part of the first data line; and a second sub-branch extending in the second direction from the first main stream, and overlapping a part of the second transmission detour line.