In a growing number of countries diplomatic systems are being overhauled so that the commercial activities of diplomatic services have been centralised, the commercial activities of diplomats have been extended, and business interests have been formally integrated within diplomatic systems. These changes result directly from the tendency of governments to reorganise, and in many cases merge, their trade and foreign ministries, as well as the strategy of building formal business–government links within diplomatic institutions. While none of these features is unfamiliar to previous diplomatic systems, what is exceptional is the relative neglect of the commercial aspects of diplomacy within diplomatic studies. This lack of attention to the commercial and business elements of diplomacy in traditional theories of diplomacy means that we find ourselves trying to analyse contemporary changes to diplomatic organisation and practice without a suitable conceptual and analytical framework. Highlighting the significance of a political economy approach to diplomacy, and also engaging with orthodox approaches to diplomacy, this article begins to develop some analytical and conceptual tools to better identify, explain and understand changes in diplomatic systems as well as the increased influence of private interests in diplomatic practice now under way.