A heat sink comprises a first thermally conductive base having a first face to thermally engage a heat-generating electronic component and a second thermally conductive base with a plurality of fins on a first face and a second face to engage the first base. The fins on the second base are positionable in either of two orientations relative to the heat-generating electronic component to which the heat sink is coupled. The fins are selectively placed in the orientation that best utilizes the direction of air flow available to the heat sink. The orientable fins of the heat sink afford flexibility in arranging the heat-generating electronic component on a circuit board or in arranging a circuit board within a computer chassis.