A display device includes a first transistor having a first semiconductor layer, in which a first source region includes a first region in contact with a first source electrode, and a first drain region includes a second region in contact with a first drain electrode. The first source and drain regions, the first region, and the second region each include a first impurity element. In a region close to an interface between the first semiconductor layer and a first insulating layer, a concentration of the first impurity element included in the first and second regions is higher than a concentration of the first impurity element included in the first source region and the first drain region. A method of manufacturing a display device includes forming a first gate electrode and a light shielding layer on a first insulating layer, and forming a second semiconductor layer on the light shielding layer.