An electronic device is provided. The electronic device includes a first housing, a second housing, the first housing slidable with respect to the second housing, a flexible display including a first display area and a second display area extending from the first display area and bendable or rollable, a battery disposed in the first housing or the second housing, and a supporting structure supporting at least a portion of the flexible display. The supporting structure includes a first area overlapping the battery and a second area extending from the first area. The first area of the supporting structure has a first thickness, and the second area of the supporting structure has a second thickness larger than the first thickness.