In modern age, the term communist party is generally used to identify any government which has adopted communist ideology. However, the Leninist concept of a communist party includes not only ideological orientation, but also a wide set of organizational policies.

The communist party is, at least according to Leninist theory, the vanguard party of the working class. Lenin theories on the role of the communist party were developed as the Russian Social Democracy was bifurcated into Bolsheviks and Mensheviks. Lenin, who was the leader of the Bolshevik ('majority') faction argued that the revolutionary party should be a well-knit vanguardist party with a centralized political command and a strict cadre policy whereas the Menshevik ('minority') faction argued that the party should be a broad-based mass movement. The Bolshevik party, which eventually transformed into the Communist Party of the Soviet Union, took power in Russia after the October Revolution. With the creation of the Communist International, the Leninist concept of Party Building was copied by emerging communist parties worldwide.

There currently exist hundreds, if not thousands, of communist parties, large and small, throughout the world. Their success rates vary widely: some are growing; others are in decline. In five countries (China, Cuba, DPR Korea, Laos, and Vietnam) communist parties retain dominance over the state. See the List of Communist Parties for details on the communist parties of today.