A heat dissipation device includes a heat sink and a fixing base for securing the heat sink to a heat-generating device. The heat sink includes a base and a pair of flanges formed on two opposite sides of the base. The fixing base includes a pair of side plates formed on a first set of two opposite sides thereof. A pair of resilient barbs extends inwards from an end portion of each side plate. The fixing base is placed on the heat sink and the resilient barbs tightly clasp first two opposite sides of the heat-generating device to press the base of the heat sink towards the heat-generating device. The flanges of the base of the heat sink abut second two opposite sides of the heat-generating device to avoid movement of the heat sink along a direction perpendicular to the flanges.