This paper explores the vertical integration of oil-producing countries. Attempts at vertical integration were prominent among oil-producing countries throughout most of the twentieth century, but particularly following the surge of resource nationalism in the 1970s. Vertical integration attempts have largely been regarded as a sideshow in the history of global oil. This article argues that vertical integration was a crucial aspect of producer country strategies into the 1970s and 1980s, and that it affected the organization of national oil industries in important ways. It does so by exploring the Norwegian case. The article demonstrates the importance of vertical integration to the long-term development of the Norwegian oil industry. It discusses the implications of these findings for the study of vertical integration in other oil-producing countries.