Piraeus B (Greek: Β΄ Πειραιώς) is a Greek election constituency that includes the Piraeus regional unit municipalities and Salamina.

Concretely, this constituency includes the municipalities of Keratsini-Drapetsona, Nikaia-Agios Ioannis Renti, Korydallos, Perama and Salamina.

It was established in 1958, primarily to separate the heavily left-voting suburbs of Piraeus from the municipality of Piraeus and diminish the electoral power of the United Democratic Left.

The members of parliament after the January 2015 election are considered below.

[11] The most votes for The River were for party chairman Stavros Theodorakis, but he chose the seat of Chania, so the seat of Piraeus B passed to Nikos Orfanos.