A portable electronic device includes a first body, a second body, a pivot assembly, and a protective assembly. The pivot assembly is pivoted to the first body and the second body and includes a shaft. The first body pivots relative to the second body via the shaft. The protective assembly is slidably disposed at periphery of the first body and the second body and includes at least one guide structure and at least one sliding structure. When the first body moves relative to the second body from a lock position to an open position, the protective assembly drives the guide structure and the sliding structure to slide along the periphery of the first body and the second body and drive the guide structure to be coaxially arranged with the shaft to allow the protective assembly to rotate with the first body relative to the second body.