The Communist Party of Iran was an Iranian communist party founded in June 1920 in Bandar-e Anzali, Gilan Province. Originally established as the Justice Party (Persian: فرقه عدالت, translit. Ferqa'ye ʿEdālat) in 1917 by the former social democrats who supported Baku-based Bolsheviks, it participated in Third International in 1919 and was renamed to the Communist Party of Iran in 1920.
Haydar Khan e Amo-oghli, one of the leaders of the Constitutional Revolution of Iran, was elected as its general secretary. Its foundation came about as a result of the establishment of the Soviet Republic of Gilan, earlier that year, by Mirza Kouchak Khan and his Jangali ("Foresters' Movement") insurgents.
The party was banned in 1921 (coinciding with the defeat of the Soviet Republic of Gilan), though members continued activities underground until the foundation of the Tudeh Party in 1941, which thereafter became the official communist party in the country.