1978 Brazilian parliamentary election

| [[File:1978 Brazilian parliamentary election - Results by constituency (Chamber of Deputies).svg|300px]] | Results by constituency of the Chamber of Deputies | [[File:1978 Brazilian parliamentary election - Results by constituency (Senate).svg|300px]] | Results by constituency of the Senate|default=2}} Parliamentary elections were held in Brazil on 15 November 1978. The pro-government National Renewal Alliance Party (ARENA) won 231 of the 420 seats in the Chamber of Deputies and 15 of the 23 seats in the Senate. Voter turnout was 82%.

They were the last elections held under a mandatory two-party system, as reforms were enacted in 1979 by Brazil's governing military junta, represented in Congress by ARENA, to allow a multi-party system to emerge in an effort to combat the growing popularity of the opposition Brazilian Democratic Movement (MDB) by splitting their vote.