An electronic device with a detachable cover comprises a main body, a cover connected to the main body, and a spring. The main body forms an opening, wherein a flange extends inwardly from an upper edge of the opening, and a first locking portion protrudes from an edge of the main body. And the cover comprises a base plate, a sliding member, and a rotating member. The base plate is received in the opening and is supported by the flange comprising an protruding tab engaging the edge of the main body and a first recess. The sliding member is slidably connected to the base plate, and comprises a second locking portion with a second recess and a first engagement member. The rotating member rotatably connected to the base plate, and comprises a second engagement member. The spring comprises a base portion and two deflected spring arms.