International Transport Services (ITS) play an important role in influencing international trade flows. This paper develops an analytical framework in which ITS costs are endogenously determined. It shows that ITS sector liberalization foster international trade very much the same way tariff liberalization does. From a political economy viewpoint, a unilateral liberalization of the sector may not always be politically feasible, and a multilateral agreement can help prop up support for reform. It is further argued that deregulation and competition policy reform are more likely to be feasible if undertaken jointly.