A display panel and manufacturing methods thereof are provided. In one example, the display panel includes a flexible substrate having a display area and a non-display area, a dam structure located in the non-display area and disposed around the display area, one or more grooves disposed on the non-display area between the display area and the dam structure, and an organic encapsulation layer. In some examples, the organic encapsulation layer covers each of the display area, at least a portion of the non-display area, and the one or more grooves. Accordingly, a display device comprising the display panel is also provided. Thus, a flatness of the organic encapsulation layer may be improved and peeling may be reduced between the organic encapsulation layer and a substrate on which the organic encapsulation layer is disposed, thereby improving an overall quality of the finished display panel.