Francesco Saverio Merlino (9 September 1856 – 30 June 1930) was an Italian lawyer, anarchist activist and theorist of libertarian socialism.

During his law studies at the University of Naples Federico II, Merlino joined the International Workingmen's Association, supporting its anarchist wing.

At the end of the 19th century, after long disputes with his friend Errico Malatesta about the relationship between anarchism and democracy, he abandoned anarchist ideas to become a theorist of libertarian socialism.

[3] Other delegates included Peter Kropotkin, Errico Malatesta, Marie Le Compte, Louise Michel and Émile Gautier.

In 1900, he defended Gaetano Bresci, an Italian-American anarchist who assassinated King Umberto I in response to the Bava-Beccaris massacre.