The Communist Party of Vietnam (CPV), also known as the Vietnamese Communist Party (VCP), is the founding and sole legal party of the Socialist Republic of Vietnam. Founded in 1930 by Hồ Chí Minh, the CPV became the ruling party of North Vietnam in 1954 and then all of Vietnam after the collapse of the South Vietnamese government following the Fall of Saigon in 1975. Although it nominally exists alongside the Vietnamese Fatherland Front, it maintains a unitary government and has centralized control over the state, military, and media. The supremacy of the CPV is guaranteed by Article 4 of the national constitution. The Vietnamese public generally refer to the CPV as simply "the Party" or "our Party".

A one-party state, single-party state, one-party system or single-party system is a governance structure in which only a single political party controls the ruling system. All other parties are either outlawed or only enjoy limited and controlled participation in elections. Sometimes the term "de facto one-party state" is used to describe a dominant-party system that, unlike the one-party state, allows democratic multiparty elections, but the existing practices or balance of political power effectively prevent the opposition from winning power.