A hinge assembly used for connecting between an arm and a display of an electronic device is provided. The display has a back surface. The hinge assembly includes a first hinge and a second hinge. The first hinge is pivoted between the display and the arm, such that the display is rotated relative to the arm. The second hinge is assembled to the first hinge. The second hinge has at least one positioning surface leaning against the back surface of the display. An electronic device using the hinge assembly is also provided.