A display device includes: a substrate; a first conductive layer on the substrate and comprising a first signal line; an insulating layer pattern on the first conductive layer; a semiconductor pattern on the insulating layer pattern; a gate insulating layer on the semiconductor pattern; and a second conductive layer comprising a gate electrode on the gate insulting layer and a first source/drain electrode and a second source/drain electrode, each on at least a part of the semiconductor pattern, wherein the insulating layer pattern and the semiconductor pattern have a same planar shape, the semiconductor pattern comprises a channel region overlapping the gate electrode, a first source/drain region on a first side of the channel region and a second source/drain region on a second side of the channel region, and the first source/drain electrode electrically connects the first source/drain region and the first signal line.