Jean-Émile Diogène Marcoux (June 12, 1877 – October 22, 1962) was a French operatic bass-baritone, known professionally as Vanni Marcoux (sometimes hyphenated as Vanni-Marcoux).
He was particularly associated with the French and Italian repertories.
His huge repertoire included an estimated 240 roles and he won renown as one of the most memorable singing-actors of the 20th century.