The Carbonari was an informal network of secret revolutionary societies active in Italy from about 1800 to 1831. The Italian Carbonari may have further influenced other revolutionary groups in France, Portugal, Spain, Brazil, Uruguay, the Ottoman Empire, and Russia. Although their goals often had a patriotic and liberal basis, they lacked a clear immediate political agenda. They were a focus for those unhappy with the repressive political situation in Italy following 1815, especially in the south of the Italian Peninsula. Members of the Carbonari, and those influenced by them, took part in important events in the process of Italian unification, especially the failed Revolution of 1820, and in the further development of Italian nationalism. The chief purpose was to defeat tyranny and establish a constitutional government. In the north of Italy other groups, such as the Adelfia and the Filadelfia, were associate organizations.

A secret society is an organization about which the activities, events, inner functioning, or membership are concealed. The society may or may not attempt to conceal its existence. The term usually excludes covert groups, such as intelligence agencies or guerrilla warfare insurgencies, that hide their activities and memberships but maintain a public presence.