The 2003 Porsche Carrera Cup Great Britain was the inaugural year for a multi-event, one make motor racing championship held across England 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 inaugural Porsche Carrera Cup Great Britain. The season began on 21 April at Mondello Park and concluded on 21 September at Oulton Park, after ten races, all in support of the 2003 British Touring Car Championship.
Barry Horne became the first drivers' champion, competing with Team Parker Racing, while Team BCR won the Teams' Championship.