Lavo Čermelj, Italianized in Lavo Cermeli (10 October 1889 – 26 January 1980) was a Slovene physicist, political activist, publicist and author. In the 1930s, he was one of the foremost representatives of Slovene anti-Fascist émigrés from the Italian-administered Julian March, together with Josip Vilfan, , and Engelbert Besednjak.