8th October Revolutionary Movement (Movimento Revolucionário 8 de Outubro, MR8) was a Marxist political organization that took part in armed struggle against the Military dictatorship in Brazil.

Today it takes part in popular political movements and publishes the newspaper Hora do Povo.

Broken up by the Brazilian army in early 1969, the remaining survivors who were still free joined the members of the Communist Dissidence of Guanabara (DI-GB), active since 1966 in political demonstrations under the leadership of Vladimir Palmeira, to form a "new" MR-8.

[1] The organization, by then already acting as an urban guerrilla, became nationally and internationally known through its central role in the kidnapping of the American ambassador in Brazil Charles Burke Elbrick, in September 1969.

[5] Besides Carlos Lamarca and Iara Iavelberg, Fernando Gabeira, Franklin Martins, Cid Benjamin, Cláudio Torres da Silva, Vera Silvia Magalhães (all of those participants in the kidnapping of Elbrick), César Benjamin, Stuart Angel Jones, Daniel Aarão Reis Filho, José Roberto Spiegner, Miguel Ferreira da Costa, João Lopes Salgado, Reinaldo Silveira Pimenta, Félix Escobar Sobrinho, Marilene Villas-Boas Pinto, Lucas Gregorio, Márcia Ferreira da Costa, Franklin de Mattos, Alfredo Iser, João Manoel Fernandes and others acted in MR-8, and many of them were killed in the fight against the military dictatorship.