Octávio Brandão Rego (Viçosa, September 12, 1896 - Rio de Janeiro, March 15, 1980) was a Brazilian pharmacist, politician and activist.

He was also a militant and theoretician in the Brazilian Communist Party (PCB in Portuguese), a movement that influenced a generation of left-wing activists and was responsible for spreading Marxist concepts in Brazil.

At the beginning of the 20th century, when the landowning oligarchy and political power were more involved in government, Brandão surprised the society of Alagoas with his libertarian concepts and attitudes.

When he was less than 20 years old, Octávio Brandão joined the fight for an eight-hour working day, which resulted in him being threatened with death by the local bourgeoisie and leaving his town.

In 1923, Octávio Brandão made the first Brazilian translation of The Communist Manifesto by Marx and Engels from the French edition by Laura Lafargue, published in the trade union newspaper Voz Cosmopolita.

The complete book was only published in April 1926 under the pseudonym Fritz Mayer and with a false indication of the place of publication in order to evade Artur Bernardes' political police.

His entire collection is housed in the Edgard Leuenroth Archive (AEL), linked to the State University of Campinas (Unicamp), including books, documents, letters and notes.