The 2018 presidential campaign of Guilherme Boulos was announced on 3 March 2018 in São Paulo.

[1] Guilherme Boulos, a nationally-recognized leader of the Homeless Workers' Movement (MTST), ran as a member of the left-wing Socialism and Liberty Party.

For the position of Vice President, Boulos chose Sônia Guajajara, an indigenous activist and former competitor for the PSOL presidential nomination, as his running mate.

[2] On 20 July, a day before PSOL national convention, the Brazilian Communist Party (PCB) confirmed their support to PSOL in the presidential election.

[3]