The European route E5 is part of the United Nations international E-road network. It is the westernmost north–south "reference road", running from Greenock in Scotland, south through Great Britain and France to Algeciras, Spain. The route is 1,900 miles (3,100 km) long.

The international E-road network is a numbering system for roads in Europe developed by the United Nations Economic Commission for Europe (UNECE). The network is numbered from E1 up and its roads cross national borders. It also reaches Central Asian countries like Kyrgyzstan, since they are members of the UNECE.