Communist Party of Switzerland (Kommunistische Partei der Schweiz), known as the "Old Communists" (Altkommunisten), was a historical Communist party, section of the Communist International.
The Party originated from a group of left-wing socialists who were expelled from the Social Democratic Party of Switzerland in 1918. Fritz Platten was a central leader in the new Party. Bulgarian communist Solomon Goldstein was among the founders.
The Swiss Communist Party was banned in 1940 because of their support of the Molotov-Ribbentrop Pact, the non-aggression pact between the Soviet Union and the Third Reich. In 1944 some of its leading members founded the Swiss Party of Labour to replace the old Communist Party.