The Lwów–Warsaw School (Polish: Szkoła Lwowsko-Warszawska) was a Polish school of thought founded by Kazimierz Twardowski in 1895 in Lemberg (Polish name: Lwów), Austro-Hungary (now Lviv, Ukraine).

Though its members represented a variety of disciplines, from mathematics through logic to psychology, the Lwów–Warsaw School is widely considered to have been a philosophical movement.^[1] Developed in the 1920s and 1930s, the school's work was interrupted by the outbreak of World War II. Despite this, its members went on to fundamentally influence modern science, notably mathematics and logic, in the post-war period.

Polish philosophy and the Lwów–Warsaw school were considerably influenced by Franz Brentano and his pupils Anton Marty, Alexius Meinong, and Edmund Husserl.

Principal topics of interest to the Lwów–Warsaw school included formal ontology, mereology, and universal or categorial grammar.

The Lwów–Warsaw School began as a general philosophical school but steadily moved toward logic. The Lwów–Warsaw school of logic lay at the origin of Polish logic and was closely associated with the Warsaw school of mathematics.

In the 1930s Alfred Tarski initiated contacts with the Vienna Circle. Tarski, the most prominent member of the Lwów–Warsaw School, has been ranked as one of the four greatest logicians of all time, along with Aristotle, Gottlob Frege, and Kurt Gödel.^[2][3][4]

In contemporary Polish learning, the philosopher Jan Woleński considers himself close to the School's heritage. In 2013 Woleński was awarded by the Foundation for Polish Science for his comprehensive analysis of the work of the Lwów–Warsaw school and for placing its achievements within the international discourse of contemporary analytic philosophy.^[5]

Many of the School's members worked in more than one field.