The hammer and sickle (☭) are a part of communist symbolism and their usage indicates an association with communism, a communist party, or a communist state. This symbol features a hammer and a sickle overlapping each other. The two tools are symbols of the industrial proletariat and the peasantry; placing them together symbolizes the unity between industrial and agricultural workers. This emblem was conceived during the Bolshevik Revolution. It is best known from having been incorporated into the red flag of the Soviet Union, along with the red star. It has also been used in other flags and emblems.

The hammer and sickle were originally a hammer on a plough, with the same meaning (unity of peasants and workers) as the better known hammer and sickle. The hammer and sickle, though in use since 1917/18, were not the official symbol until 1922, before which the original hammer and plough insignia was used by the Red Army and the Red Guard on uniforms, medals, caps, etc.

Later, the symbol was featured on the flag of the Soviet Union, adopted in 1923 and finalized in the 1924 Soviet Constitution, and flags of the republics of the Soviet Union after 1924. Before this, the flags of Soviet republics tended to be a plain red field, with the golden text of the name of the respective republic superimposed on it, as written in Article 90 of the 1918 Soviet Constitution.