The General Motors H platform (or H-body) is an automobile platform used by subcompact cars from the 1971 to 1980 model years. The first subcompact car design developed by GM, the rear-wheel drive H platform initially underpinned the Chevrolet Vega and its Pontiac Astre counterpart. For 1975, the H platform was expanded from entry-level vehicles to sport compacts, adding the Chevrolet Monza, Buick Skyhawk, Oldsmobile Starfire, and Pontiac Sunbird. In contrast to the globally-developed T platform (later sold alongside it), the H-platform was sold nearly exclusively in North America.