GMC is the truck division of the General Motors Company. It was formed by the purchase, in 1909, of Max Grabowski's Rapid Motor Vehicle Company, which had developed some of the earliest commercial trucks ever designed. Grabowski's trucks used a one-cylinder engine. That same year, GM purchased another manufacturer, the Reliance Motor Car Company.

In 1911 Rapid and Reliance merged, and a year later, under the marque GMC Truck, they first presented at the New York Auto Show. That year, 22,000 trucks were produced, but only 372 were GMC's. That number would dramatically increase during World War II, when GMC Truck produced 600,000 trucks for use by the US military.

GM purchased controlling interest in Yellow Coach, a Chicago, Illinois-based bus manufacturer, in 1925, and then purchased the remaining interest in 1943, after which the company was renamed GM Truck and Coach Division. It produced transit and inter-urban buses in Canada and the US until the 1980s, but, facing steep competition, it stopped producing buses at that time. GMC's bus models were sold in 1987, to Transportation Manufacturing Corporation (also Motor Coach Industries in Canada), and later NovaBus.

Now known simply as GMC, the brand is used on trucks, vans and SUVs marketed by General Motors in North America and the Middle East. GMC was GM's 2nd largest selling light vehicle division after Chevrolet in January 2007.