Embodiments of the present disclosure provide an array substrate including a base substrate, an active layer on the base substrate, a first gate insulating layer on the active layer, a first gate on the first gate insulating layer, and a second gate insulating layer on the first gate. The second gate insulating layer includes a first sub-insulating layer and a second sub-insulating layer disposed in a direction away from the active layer, and a hydrogen content of the first sub-insulating layer is larger than a hydrogen content of the second sub-insulating layer. A method for fabricating the array substrate and a display panel including the array substrate are also provided.