A Polish joke is an ethnic joke intended to mock the Polish people in the English language based on the hostile stereotypes about them. A 'Polish joke' belongs to the category of conditional jokes (i.e., jokes whose understanding requires from the audience a prior knowledge of what a Polish joke is). Similar to all discriminatory jokes, they depend upon the audience's preconceived notions and affective dislikes for entertainment. The relationship between these internalized negative stereotypes about the Polish people and the persistence of ethnic jokes about them is not easy to trace, although they can be understood by many. Often an offensive term for the Poles themselves is used in the joke description as well, for example the Polack joke in English.
Some of the early 20th century Polish jokes might have been told originally before World War II in disputed border-regions such as Silesia, suggesting that Polish jokes did not originate in Nazi Germany, but a lot earlier, as an outgrowth of regional jokes rooted in historical social class differences. Nonetheless, these jokes were later fuelled by ethnic slurs disseminated by German warlords and National Socialist propaganda that attempted to justify the Nazi crimes against ethnic Poles by presenting them as dirty and relegating them as inferior on the basis of not being German.
Polish Americans became the subject of derogatory jokes at the time when Polish immigrants moved to America in considerable numbers fleeing mass persecution at home perpetrated by Frederick the Great and Tsar Nicholas I. They took the only jobs available to them, usually requiring physical labor. The same job-related stereotypes persisted even as Polish Americans joined the middle class in the mid 20th century. "These degrading stereotypes were far from harmless. The constant derision, often publicly disseminated through the mass media, caused serious identity crises, feeling of inadequacy, and low self-esteem for many Polish Americans." During the Cold War era, despite the sympathy in the US for Poland being subjected to communism, negative stereotypes about Polish Americans endured, mainly because of the Hollywood/TV media involvement.