A display device according to an embodiment includes: a first metal layer disposed on a substrate; a first insulating layer disposed on the first metal layer; a first transistor disposed on the first insulating layer and including a semiconductor layer; and a light-emitting device electrically connected to the first transistor, wherein the first metal layer includes a first portion with a first thickness and a second portion with a second thickness, the second thickness is greater than the first thickness, and the semiconductor layer is electrically connected to the first metal layer.