In an assembly of an electronic device and a battery, the battery includes a protrusion that is formed with an engaging hole, and the electronic device includes a housing and an engaging unit. The housing defines a receiving space and is formed with a first opening that is adapted for extension of the protrusion. The engaging unit includes a main body pivotable relative to the housing, an actuating member accessible from outside of the receiving space, and an engaging hook disposed on the main body adjacent to the first opening. The engaging hook is engageable with the engaging hole in the protrusion. The actuating member is actuable to pivot the main body so as to disengage the engaging hook from the engaging hole.