Like many other fall and winter weather choices, today's fashionable trench coat is military in origin. Lightweight and rain-resistant, it was created as an alternative for officers and other ranked personnel during World War I, which was, of course, dominated by trench warfare. The coat is somewhat common; however, it is often easy to forget its origin, even though many of the details we consider hallmarks of the trench coat's style actually originated as military practicalities for the display of insignia and the carrying of equipment and weapons.

Military clothes have always had a presence in civilian fashion, usually because they are retained after war both for durability and as an indicator of status as a veteran or survivor. The trench coat was no different, and because its use had been restricted to those of rank, it quickly morphed into an indicator of wealth and sophistication. Civilian versions of the trench coat for both men and women began to be produced between the two world wars, and the military version of the coat remained in use during World War II, although in more variants as more countries added similar garments to their uniform options.

After WWII, the trench coat's trendiness really took off, and the coat became a staple of fashion in both books and films, particularly the detective genre. Perhaps most surprising, though, is the way the trench coat has been embraced by various alternative youth fashion movements for decades.

The trench coat was popular with the mods in the 1960s and is often seen in both the goth and heavy metal scenes (although usually in longer, black versions more accurately known as dusters). In more mainstream fashion, Sex in the City's Carrie also popularized the trench coat for women by making it sexy and flirty. For a coat that started in battle, the trench coat has had a surprising fashion history that is only likely to continue.