Line 5, currently known as Cornellà Centre – Vall d'Hebron, its termini, and often called "Línia Blava" (Blue line), is a rapid transit metro line belonging to the Barcelona Metro network operated by TMB, and part of the ATM fare-integrated transport network.

It opened in 1959 as the line 2 (originally).

Line 5 is 18.8 km (11.7 mi) long and has 26 stations, from Cornellà to Vall d'Hebron in the northern part of Barcelona, where it meets L3.