Moneta became active in the peace movement in 1870. In 1878 he helped establish the League of Liberty, Brotherhood and Peace in Milan. In 1887 he helped to found the Society for International Peace and Justice, and the Lombard Union for International Peace and Understanding, of which he became president. Moneta regularly attended international peace congresses, and from 1895 onwards he was a member of the Permanent Interntional Peace Bureau. He actively worked to establish better understanding between countries on the verge of conflict, especially through arbitration.