The Galileo Circle (Galilei Kör) was an atheist-materialist student organization that functioned in Budapest between 1908 and 1919. Their center was located at the Anker Köz in Terézváros, Budapest. The circle had several subgroups with four different world views: the radical liberals (they called themselves as "radical democrats"), the Marxists (they called it as "Revolutionary Socialists"), the anarcho-syndicalists and the socialists (social democrats). However they had common goals, which included the protection of free scientific research and thinking at universities, the cultivation of social sciences, the social assistance of poor students, the spread of anti-clericalist and atheist views, the support of anti-nationalism and promoting internationalism, the propagation of anti-alcoholism, the opposition to large estates and the "reorientation of Hungarian social perception".

The circle was founded on 22 November 1908. This was in response to the attacks on Gyula Pikler, a social scientist who had suggested that the nation was a social phenomenon which arose through a social and historical process, rather than an eternal entity. This led to him being attacked by Hungarian Christian nationalists. It claimed to be specifically apolitical and declared itself in favour of self-education and science. Endre Ady described the galilesists as the 'young army of Fever', dedicating various poems to the Circle. Oszkár Jászi thought the galileists would help lead Hungary from 'the Balkans into Western Europe'.

The organisation was banned in January, 1918, a period of labour unrest in the Austro-Hungarian Empire. However following the Aster Revolution in October 1918 it was relaunched. It was finally dissolved on 21 March, shortly following the establishment of the Hungarian Soviet Republic.

The circle published Szabadgondolat. The Sonntagskreis is often considered as a smaller successor organisation of Galileo Circle in Germany, but its membership required at least a finished university degree. However the Sonntagskreis preferred rather the membership of scholars.

In the interwar period, following the dissolution of the Circle, Hungarian conservative intellectuals criticised the Galileists for having instigated the Aster Revolution, their contribution in the disarmament of the Hungarian army when other nations started to claim large territories from Hungary, their activity led to the tragic events of the Hungarian Soviet Republic and for being responsible for the decisions of the Treaty of Trianon, which resulted in the loss of 70% of the pre-war territory of Hungary and 64% of the pre-WW1 era population.

In Kingdom of Hungary, the universities were church-founded institutions from the Middle Ages until the last quarter of the 19th century. Initially, in the Middle Ages, the Catholic Church, then after the Reformation, the Protestant churches also founded their own universities. The state did not have any universities, with the exception of a military academy and a few engineering universities from the 18th century. A radical change that broke the monopoly of churches on the fields of humanities came at the last quarter of the 19th century, when one after another state-funded colleges and universities appeared. Despite the vehement protests of Catholic and Protestant church leaders of the country, these universities offered courses in the humanities, where the traditional religious philosophies were completely eclipsed. Referring to the autonomy of the universities, these new state-financed educational institutions also offered wide degree of freedom for the materialist and evolutionist worldviews. The churches, however, did not let go of their monopoly over the humanities, and began to organise religious students into communities to counter what they called "modern anti-Christian philosophical and moral views" in the state-financed public universities.

"My aim is to eradicate such petty notions as homeland and nation from your hearts."

— Lecture by Gyula Pikler, full professor of philosophy of law, 1901