XXXX (pronounced 'Four-ex') is a German style lager beer brewed in Milton, Australia by Queensland brewers, Castlemaine-Perkins, a brewery originally located in Castlemaine, a goldrush town in Victoria, Australia. Its name, first introduced in 1924, is a throwback to the long standing tradition of using X's to indicate the strength of an ale.

It contains 4.8% Alcohol/Volume. Described to be bland but palatable (with a distinct bitter aftertaste), its frequent imbibing leads to fierce loyalty toward the subject matter. Although generally only available in Queensland, it competes locally with Victoria Bitter and Toohey's New, and not, contrary to popular belief outside Australia, with Fosters. In fact, Fosters (an international Australian icon) is sometimes rarely seen in most of Australia these days!

Not to be confused with the made up pornographic classification system of the same name, frequently seen in spam email subjects.