The present disclosure provides an electronic device, a mobile terminal and an antenna assembly. The electronic device includes: a case defining an accommodating groove; a movable support slidably connected to the case, and capable of moving out of or retracting into the accommodating groove; and a first antenna installed on the movable support. Since the first antenna may be ejected out of the accommodating groove along with the movable support, influence of other components disposed inside the electronic device on the first antenna may be reduced. Thus, the implementation of the present disclosure may improve antenna performance of the electronic device.