A duffel coat (also duffle coat) is a coat made from duffel cloth, designed with toggle-and-rope fastenings, patched pockets and a large hood. The name derives from Duffel, a town in the province of Antwerp in Belgium where the manufacturing process of this kind of fabric, a coarse, thick, woolen cloth originated. Duffel bags were originally made from the same material.

As the hood and toggle fastenings from Polish frocks proved popular, the frock spread across Europe by the 1850s. By 1890 a less sophisticated version was being supplied to the British Royal Navy, from various manufacturers. During World War II all British troops wore the coat, among them Field Marshal Sir Bernard Montgomery and Lieutenant-Colonel Sir David Sterling. After the war, the coats became available in England as government surplus stock and became popular, especially with students. In countries freed by British troops from Nazi-German occupation, wearing the coat also meant a tribute to all troopers that fought in the war and a statement to civilian freedom.