The political slogan "Workers of the world, unite!" is one of the most famous rallying cries from The Communist Manifesto (1848)[1][2][3][4] by Karl Marx and Friedrich Engels (German: Proletarier aller Länder vereinigt Euch!, literally "Proletarians of all countries, unite!",[5] but soon popularised in English as "Workers of the world, unite! You have nothing to lose but your chains!").[5][note 1] A variation of this phrase ("Workers of all lands, unite") is also inscribed on Marx's tombstone.[7] The essence of the slogan is that members of the working classes throughout the world should cooperate to defeat capitalism and achieve victory in the class conflict.

The Use as official motto by the Czechoslovak Socialist Republic: