The Open Society and Its Enemies is a work on political philosophy by the philosopher Karl Popper, in which the author presents a "defence of the open society against its enemies", and offers a critique of theories of teleological historicism, according to which history unfolds inexorably according to universal laws. Popper indicts Plato, Hegel, and Marx for relying on historicism to underpin their political philosophies.

Sir Karl Raimund Popper was an Austrian–British philosopher, academic and social commentator. One of the 20th century's most influential philosophers of science, Popper is known for his rejection of the classical inductivist views on the scientific method in favour of empirical falsification. According to Popper, a theory in the empirical sciences can never be proven, but it can be falsified, meaning that it can be scrutinised with decisive experiments. Popper was opposed to the classical justificationist account of knowledge, which he replaced with critical rationalism, namely "the first non-justificational philosophy of criticism in the history of philosophy".