The Transportation Corps is a combat service support branch of the U.S. Army. It is responsible for the movement of personnel and material by truck, rail, air, and sea. It is one of three U.S. Army logistics branches, the others being the Quartermaster Corps and the Ordnance Corps. The Corps was established in its current form on 31 July 1942, with predecessor services dating back to the American Civil War. The Transportation Corps is currently headquartered at Fort Gregg-Adams, Virginia. The officer in charge of the branch for doctrine, training, and professional development purposes is the Chief of Transportation (CoT) and Commandant of the US Army Transportation School, currently held by BG Beth A. Behn. The Corps's motto is "Nothing Happens Until Something Moves".

The term combat service support is utilized by numerous military organizations throughout the world to describe entities that provide direct and indirect sustainment services to the groups that engage in combat.