A mobile electronic device includes a display including a flat portion, a first side portion extending from one side of the flat portion, and a second side portion formed extending from another side of the flat portion; and a frame including a flat part disposed under the flat portion of the display, a first side part formed at a first edge of the flat part, and a second side part formed at a second edge of the flat part, the flat part being disposed between the first side part and the second side part. The display includes an external protective layer and a panel module disposed under the external protective layer. The first side part includes a first support portion and a second support portion formed adjacent to the first support portion and having a step difference with the first support portion.