A button assembly for an electronic device includes a button and an elastic member. The button includes a cap, and a latch member for latching to the cover. The elastic member includes a first resisting portion, a second resisting portion, and an elastic main portion connecting the first resisting portion to the second resisting portion. A cavity in the elastic main portion allows the cap to be driven to press against the first resisting portion. An electronic device using the button assembly is also provided.