The Willys MD, formally the M38A1 Truck, Utility: 1/4 ton, 4x4, or the G‑758 by its U.S. Army Standard Nomenclature supply catalog designation, was a four-wheel drive, military light utility vehicle, made by Willys and Willys Motors / Kaiser Jeep from 1952 to 1971. It was widely procured by the U.S. military from 1952 until 1957, after which U.S. purchases were reduced to the U.S. Marine Corps. The Marine version had minor differences from the units used by other branches.

Willys was a brand name used by Willys–Overland Motors, an American automobile company, founded by John North Willys. It was best known for its design and production of World War II–era military jeeps (MBs), Willys M38 and M38A1 military jeeps as well as civilian versions, and branding the 'jeep' military slang-word into the '(Universal) Jeep' marque.