Louis Loucheur (12 August 1872 in Roubaix, Nord – 22 November 1931 in Paris) was a French politician in the Third Republic, at first a member of the conservative Republican Federation, then of the Democratic Republican Alliance and of the Independent Radicals. Harold Nicolson, in "Curzon The Last Phase 1919-1921," wrote, in his biographical footnote on Loucheur, "one of the most reasonable and intelligent of French post-war experts; not a politician."