A storage device assembly includes a storage device (40), a cover (30), a button (10) and a bracket (20). The storage device includes a tray (44). The cover defines a button slot (34) and a pair of apertures (38) therein. The bracket is removably attached to the cover, and includes a pair of resilient legs (25). A pair of latches (26) is formed on the legs of the bracket respectively. The button is received in the button slot of the cover. The button is slidable relative to the bracket between an open position and a closed position. In the closed position, the button deforms the legs in opposite directions and drives the latches to protrude out beyond the apertures respectively, thereby locking the tray. In the open position, the legs rebound and the latches are withdrawn from the apertures respectively, and the tray can be ejected.