A display device includes a first thin-film transistor (TFT) including a first semiconductor layer including silicon semiconductor and a first gate electrode insulated from the first semiconductor layer, a first interlayer insulating layer covering the first gate electrode, a second TFT arranged on the first interlayer insulating layer and including a second semiconductor layer including oxide semiconductor and a second gate electrode insulated from the second semiconductor layer, a second interlayer insulating layer covering the second gate electrode, a first power supply voltage line arranged on the second interlayer insulating layer, a first planarization layer covering the first power supply voltage line, and a data line arranged on the first planarization layer and at least partially overlapping the first power supply voltage line.