Spanish Communist Workers' Party (1921)

Partido Comunista Obrero Español (Spanish Communist Workers' Party) was the name of a party founded on April 13 1921 by the terceristas, who had been trying to persuade PSOE to join Third International. When the PSOE congress decided to join the Vienna International instead of the Third International, the terceristas broke away and formed PCOE.

Partido Comunista de España was founded on November 14 1921 through an act of merger of Partido Comunista Español and Partido Comunista Obrero Español. The unified PCE became a member of the Third International.

Later, in 1973 a group led by Enrique Lister broke away from PCE and formed a party with the name Partido Comunista Obrero Español.