Curtinism is the fundamental belief that any unit of measurement can be converted into imperial pints.

Curtinism is believed to have its roots in Irish popular culture of the late 19th century or early 20th century. Research in the last twenty years has established with reasonable certainty that Curtinism was an inevitable development in a country in which a pint of stout or beer has a status similar to that of water or milk in civilised countries. It was esssential for any Irishman to be able to determine how many pints could be obtained if something else was either sold or not acquired to begin with. Nowadays, followers of Curtinism can mostly be found in the counties of Cork and Longford, as well as - in small numbers - in local Irish enclaves in the cities of Las Vegas, USA and Munich, Germany. In the latter, Irish expatriats are to this day attempting to establish the pint as the new standard unit, effectively replacing Munich's current Maß (also see Steinism). Although the Munich movement gained some momentum in 1985, its popularity has since waned.

Some scholars uphold that its name is based on a misspelling of the English word curtain, going back to the widespread use in the 17th century of curtains and wallpapers depicting stylised pint glasses in the pubs of counties Donegal and Galway in the North and West, respectively, of the Republic of Ireland.

However, most researchers now agree that for the first 100 years of its existence, the belief of Curtinism existed without actually having a name to refer to it by. The name was introduced by a Corkonian who realised that 90% of his friends and family believed in a faith that did not have a name. Quite unceremoniously, he named it after himself. There is still some dispute whether that Corkonian was James Curtin, a British wrestler, or the less well-known James A. Curtin, a disgruntled former Pizza Hut employee. Those contesting that the wrestler was the originator of the name Curtinism point to the fact that he is not even Irish, let alone Corkonian. Those contesting James A. Curtin's creatorship claim that there never was a James A. Curtin working at any Pizza Hut in the Republic of Ireland.