A fingerprint sensor and a display device include a substrate. A circuit element layer is disposed on a first surface of the substrate and includes a semiconductor layer, conductive layers and at least one opening portion. A light emitting element layer is disposed on the circuit element layer and includes at least one light emitting element. A sensor layer is disposed on a second surface of the substrate and includes at least one light sensor corresponding to the opening portion. The opening portion is defined by non-overlapping of the semiconductor layer and the conductive layers, the opening portion has a closed loop shape in plan view, and at least a portion of the closed loop shape includes a curve, or an internal angle of the at least a portion of the closed loop shape is an obtuse angle.