Ernesto Teodoro Moneta (September 20, 1833, in Milan, Lombardy – February 10, 1918) was an Italian journalist, nationalist, revolutionary soldier and later a pacifist and Nobel Peace Prize Laureate. He adopted the motto In varietate unitas!.

At age 15, Moneta participated in the "Five Days of Milan" (1848 uprising against Austrian rule). He later attended the military academy in Ivrea. In 1859 he joined Garibaldi's Expedition of the Thousand, and also fought in the ranks of the Italian army against the Austrians in 1866.

Subsequently, he became an international peace activist, despite his strong Italian nationalism.

Between 1867 and 1896 he was editor of the Milan democratic paper Il Secolo, published by Edoardo Sonzogno.

In 1887 he founded the Lombard Association for Peace and Arbitration (Unione Lombarda per la Pace e l'Arbitrato), which called for disarmament and envisaged the creation of a League of Nations. He won (with Louis Renault) the Nobel Peace Prize in 1907.

In the last years of his life, however, Moneta's Italian nationalism reasserted itself and got the better of his pacifism. He expressed public support for both the Italian Conquest of Libya in 1912 and Italy's entry into the First World War in 1915.