A type of beer that is fermented and conditioned at low temperatures, normally using a bottom-fermenting yeast. Pale lager is the most widely consumed and commercially available style of beer in the world. Bock, pilsner and märzen are all styles of lager. There are also dark lagers, such as dunkel and schwarzbier.

While cold storage of beer, 'lagering', for example in caves, was a common practice throughout the medieval period, bottom-fermenting yeast seems to have emerged as a hybridisation in the early 15th century through natural selection, producing beer more attenuated, cleaner, rounder and less fruity than ales. The modern rise of lager was linked to the development of refrigeration, which made it possible to brew lager year-round and also made it possible to brew lager in more places and keep it cold until serving.

The typical lager in worldwide production is a pale and lightly-flavoured lager in the Dortmunder or pilsner styles.