A slidable assembly for an electronic device includes a housing, a slidable button, and a stopper. The housing defines a receiving groove, a slot, and a plurality of ports. The slidable button is slidably received in the receiving groove, and includes a seal ring for sealing the plurality of ports. The stopper is attached to the slot of the housing for abutting one side of the slidable button and stopping the slidable button from sliding out of the receiving groove. The slidable button is slid in the receiving groove to expose or cover the plurality of ports.