The neoclassical theory of international trade presupposes given supplies of factors of production, including labor, and their international immobility. The price of a factor of production is then determined by its value productivity, which in turn depends on physical productivity and the price of the product. This can be clearly seen, for example, in arguments leading to the Stolper–Samuelson theorem that the price of a factor of production that is used relatively more intensively in the production of importables is increased by the imposition of an import tariff. In other words, the price of a factor of production as a quasi-rent is determined exclusively by the demand for it, since the supply is given by assumption.

The neoclassical interpretation of the Ricardian theory of international trade is, naturally, that it is a special case of the more general neoclassical theory, where the labor is the sole factor of production and the specialization is complete rather than incomplete.