The Defenestrations of Prague (Czech: Pražská defenestrace, German: Prager Fenstersturz, Latin: Defenestratio Pragensis) were three incidents in the history of Bohemia in which people were defenestrated (thrown out of a window). Though already existing in Middle French, the word defenestrate ("out of the window") is believed to have first been used in English in reference to the episodes in Prague in 1618 when the disgruntled Protestant estates threw two royal governors out of a window of the Hradčany Castle and wrote an extensive apologia explaining their action. In the Middle Ages and early modern times, defenestration was not uncommon—the act carried elements of lynching and mob violence in the form of murder committed together.

The first governmental defenestration occurred in 1419, second in 1483 and the third in 1618, although the term "Defenestration of Prague" more commonly refers to the third. Often, however, the 1483 event is not recognized as a "significant defenestration", which leads to some ambiguity when the 1618 defenestration is referred to as the "second Prague defenestration". The first and third defenestrations helped to trigger a prolonged religious conflict inside Bohemia (the Hussite Wars, 1st defenestration) or beyond (Thirty Years' War, 3rd defenestration), while the second helped establish a religious peace in the country for 31 years (Peace of Kutná Hora, 2nd defenestration).