This article is about a legal concept, not a political union of territories (confederation), also known in Poland as "konfederacja".

A konfederacja (Polish for "confederation") was an ad hoc association formed by Polish-Lithuanian szlachta (nobility), clergy, cities, or military forces in the Polish-Lithuanian Commonwealth for the attainment of stated aims. A konfederacja often took the form of an armed rebellion aimed at redressing perceived abuses or trespasses of some (e.g. royal) authority. Such "confederations" acted in lieu of state authority or to force their demands upon that authority. They could be seen as a primary expression of direct democracy and right of revolution in the Commonwealth, and as a way for the nobles to act on their grievances and against the state's central authority.