The disclosure provides a display panel, a manufacturing method thereof, and a display device. The display panel includes a substrate layer, a gate layer, an insulating layer, and an active layer. The gate layer is disposed on the substrate layer and includes a first gate layer and a second gate layer. The second gate layer is disposed on a surface of the first gate layer. The insulating layer covers the gate layer and the substrate layer. The active layer is disposed on a surface of the insulating layer away from the gate layer. The active layer includes a first layer section and a second layer section connected to the first layer section, and a surface of the second layer section is above a surface of the first section layer.