An exemplary stylus includes a barrel, two slide mechanisms, two housings and a head. The two housings are slidably coupled to the barrel by the two slide mechanisms. The head is attached to an outer end of one of the housings, and configured to contact a touch screen of an electronic device. The two housings cooperatively surround the barrel when the stylus is in a retracted position, and are slidable along two opposite directions to elongate the stylus.