The 2004 Porsche Carrera Cup Great Britain was a multi-event, one make motor racing championship held across England, Scotland and Ireland. The championship featured a mix of professional motor racing teams and privately funded drivers, competing in Porsche 911 GT3 cars that conform to the technical regulations for the championship. It forms part of the extensive program of support categories built up around the BTCC centrepiece.
This season was the second Porsche Carrera Cup Great Britain. The season began on 10 April at Thruxton Circuit and concluded on 27 September at Donington Park, after 20 races held at ten meetings, all in support of the 2004 British Touring Car Championship.
Richard Westbrook became the drivers' champion driving for Redline Racing.