A red star, five-pointed and filled, is a symbol that has often historically been associated with communist ideology, particularly in combination with the hammer and sickle, but is also used as a purely socialist symbol in the 21st century. It has been widely used in flags, state emblems, monuments, ornaments, and logos.

One interpretation sees the five points as representing the five fingers of the worker's hand, as well as the five populated continents (counting the Americas as one). A lesser-known suggestion is that in communist symbolism, the five points on the star were intended to represent the five social groups that would lead Russia to communism: the youth, the military, the industrial labourers, the agricultural workers or peasantry and the intelligentsia. In Soviet heraldry, the red star symbolized the Red Army and military service, as opposed to the hammer and sickle, which symbolized peaceful labour.

Different countries across Europe treat the symbol very differently. Some former Warsaw Pact nations have passed laws banning it, claiming that it represents "a totalitarian ideology", but other Eastern European countries hold a very positive view of it as a symbol of antifascism and resistance against Nazi occupation. Red Star has also been used in a non-communist context and before the emergence of this movement, in symbols of countries and states since the 19th Century. It appears for example on the flags of New Zealand and the U.S. state of California. Red star has also been used as logo by private agencies and corporations, such as the oil giant Texaco and beer multinational Heineken.