A display device includes a substrate, a plurality of pixels disposed on the substrate, an encapsulation layer disposed above the plurality of pixels and comprising an organic encapsulation film, a dam structure disposed on the substrate and surrounding an outer boundary of the plurality of pixels, and crack detection lines comprising an output line disposed on the dam structure without overlapping with the organic encapsulation film, and an input line electrically connected to the output line and disposed on the organic encapsulation film.