This is an exploration of the internationalization of the service sector through an analysis of the international growth and development of UK business service firms. The author traces the evolution of service multinational organizational structures within the advertising, accountancy and computer services sectors. The analysis of the survey and case study evidence provides important insights into the process of internationalization among UK business service firms. A variety of organizational strategies and structures are identified and subjected to examination. Drawing on theoretical literature concerning international trade and investment, and the organization of the firm, a framework is developed within which the internationalization of business service firms can be understood. The wider relevance of this framework is considered and suggestions for further research are forwarded.