The 1984 Supertaça Cândido de Oliveira was the 6th edition of the Supertaça Cândido de Oliveira, the annual Portuguese football season-opening match contested by the winners of the previous season's top league and cup competitions (or cup runner-up in case the league- and cup-winning club is the same). The 1984 Supertaça Cândido de Oliveira was contested over two legs, and opposed Benfica and Porto of the Primeira Liga. Benfica qualified for the SuperCup by winning the 1983–84 Primeira Divisão, whilst Porto qualified for the Supertaça by winning the 1983–84 Taça de Portugal.
The first leg which took place at the Estádio da Luz, saw Benfica defeat Porto 1–0. The second leg which took place at the Estádio das Antas, saw Porto emulate the first leg result (1–1 on aggregate), which led to the match being replayed one month later over two legs. In the replay, Porto won both matches over the Águias and thus claimed a third Supertaça.