The Convention on International Transport of Goods Under Cover of TIR Carnets (TIR Convention) is a multilateral treaty that was concluded at Geneva on 14 November 1975 to simplify and harmonize the administrative formalities of international road transport. (TIR stands for "Transports Internationaux Routiers" or "International Road Transports".) The 1975 convention replaced the TIR Convention of 1959, which itself replaced the 1949 TIR Agreement between a number of European countries. The conventions were adopted under the auspices of the United Nations Economic Commission for Europe (UNECE). As of May 2013, there are 68 parties to the Convention, including 67 states and the European Union.

The TIR Convention establishes an international customs transit system with maximum facility to move goods. The TIR system not only covers customs transit by road but a combination is possible with other modes of transport (e.g., rail, inland waterway, and even maritime transport), as long as at least one part of the total transport is made by road. Truckers making use of the TIR procedure must first obtain an internationally harmonized customs document, referred to as a TIR carnet. TIR carnets are issued by national road transport associations. This customs document is valid internationally and as well as describing the goods, their shipper and their destination, represents a financial guarantee. When a truck arrives at a border customs post it need not pay import duties and taxes on goods at that time. Instead the payments are suspended. If the vehicle transits the country without delivering any goods, no taxes are due. If it fails to leave the country with all the goods, then the taxes are billed to the importer and the financial guarantee backstops the importer's obligation to pay the taxes. TIR transits are carried out in bond, i.e. the lorry must be sealed as well as bearing the carnet. The security payment system is administered by the International Road Transport Union (IRU).