A microbrew (alternatively called a microbrewery) is a relatively new term for a small commercial brewery.

The term and trend originated in the United States in the late 1980s.

Earlier in the century, Prohibition had driven many breweries into bankruptcy, as they could not rely on selling "sacramental" wine like wineries of that era did. After the consolidation of breweries through the subsequent decades, most American commercial beer was produced by a few very large corporations, producing a very uniform mild-tasting lager. Consequently, some beer drinkers craving variety turned to homebrewing and eventually a few started doing so on a slightly larger scale. For inspiration, they turned to Britain, Germany, and Belgium, where a centuries-old tradition of artisan beer production had never died out.

The popularity of these products was such that the trend quickly spread, and hundreds of these small breweries sprung up, often attached to a bar, known as a "brewpub," where the product could be enjoyed.

Similar breweries are gradually making appearance in other countries, for instance New Zealand and Australia, where a similar market concentration had occurred.