A roof rack system has a clamping system comprised of handles, an actuator, and a pair of jaws. The jaws provide a universal clamping system that will attach to most roof rack cross bars with an easy-on/easy-off, quick-release actuator, such as a ratcheting mechanism or lever system, that will integrate with a wide variety of accessories. The preferred actuator includes a lever mechanism with a linkage between the trigger handle and the elongated handgrip. An adjustment knob is used to adjust the longitudinal distance of the distal end of the linkage from the back end of the handgrip. This system is easier to use, more versatile, and less expensive than conventional roof rack accessory systems.