A heat dissipation assembly comprises a mounting seat, a heat sink and a clip for fastening the heat sink in the mounting seat. The mounting seat defines an opening and is provided with a first and second protrusions. The heat sink is accommodated in the opening of the mounting seat. The clip comprises an elongated pressing member for pressing the heat sink and a clamping leg connected to one end of the pressing member and attached to the first protrusion of the mounting seat. An operating member, defining a notch, is pivotably attached to the other end of the pressing member and is rotatable relative to the pressing member and the second protrusion of the mounting seat slides in the notch of the operating member so that the clip switches between a release status and locking status.