A clip (30) for securing a heat sink (50) to a heat-generating electronic device (90) includes first and second fasteners (40, 60). The first fastener includes a body (41), and a pair of legs (49) depending from respective opposite ends of the body. The body has a stretch portion (411) in which cutouts (413) are defined to form a pair of fixing tabs (415). A pair of spring pressing portions (43) is formed at respective opposite ends of the body. Each spring pressing portion has a pressing tab (451) to be received in a slot (53) defined in the heat sink. The second fastener has a vertical panel (61) defining an opening (62) adapted to receive a clasp (72) of a retention module (70), and a slot (63) for receiving the fixing tabs of the first fastener therethrough. The fixing tabs are then deformed to secure the second fastener to the first fastener.