Abstract: A display device includes a circuit layer disposed on a substrate and including a first transistor, and a light-emitting element disposed on the circuit layer and electrically connected to the first transistor. The first transistor includes a first active area, a first drain electrode disposed on a side of the first active area, a first source electrode disposed on another side of the first active area, a gate insulating film disposed on the first active area, an oxygen-providing film disposed on the gate insulating film, and a first gate electrode disposed on the oxygen-providing film. The oxygen-providing film has a higher oxygen ratio than the gate insulating film.