Altbier (often abbreviated to Alt) is the name given to a form of German top-fermenting beer that originated in Westphalia and spread to parts of the Rhineland later.

The name Altbier, which literally means old [style] beer, refers to the pre-lager brewing method of using a warm top-fermenting yeast like British pale ales. Over time the Alt yeast adjusted to lower temperatures, and the Alt brewers would store or lager the beer after fermentation, leading to a cleaner, crisper beer than is the norm for an ale.