Abstract: A clip for attaching and supporting wall panels to a building (such as for an exterior building envelope), a wall panel system, and systems and methods for supporting wall panels is provided. The clip includes a main body portion, a first extension portion, a second extension portion, and a face portion. The clip is used with a system of interlocking vapor barrier wall panels to support the wall panels and affix them to a building frame without compromising the vapor barrier. Exterior façade panels can also be affixed to the clip and building frame without compromising the vapor barrier.