Linha do Sul is a Portuguese railway line which connects Campolide A, in Lisbon, and , in the Algarve. The first section, from to , was opened in 1861. The route to opened on 25 May 1920. In 2003 it was linked to Lisbon, crossing the Tagus on the 25th of Abril Bridge.
The section between Pinhal Novo and Funcheira was classified as Linha do Sado until 1992, while the section from to via and was classified as Linha do Sul.