An exemplary hinge assembly includes a rotatable shaft, a rotatable stand, a fixed stand, a restricting member, a cam, and a fastening member. The rotatable stand and the restricting member are non-rotatably connected to the rotatable shaft. The fixed stand and the cam are rotatably connected to the rotatable shaft. The cam is fixed to the fixed stand. The cam defines a restricting groove. A restricting piece is formed on the edge of the restricting member. The restricting piece engages in the restricting groove of the cam, thereby defining a rotatable angle range between the rotatable stand and the fixed stand.