ABSTRACT Innovation studies scholars use the concept of ‘spillovers’ to explain how ideas and people move among firms and industries and how regions form industrial clusters. Historians of technology use different vocabularies, but are interested in similar exchanges. This special issue explores spillovers specifically from (and to) oil firms. Oil touches all of social life, including non-oil technologies, but historians of technology and innovation studies scholars have not grasped its ubiquity. Within history of technology, oil history is a circumscribed subfield that has drawn little attention to non-oil technological activity performed or supported by oil actors, while historians of non-oil and non-energy technologies do not sufficiently acknowledge that the technologies that they write about are shaped by their energetic context. Within innovation studies, meanwhile, oil is also a relatively minor topic, despite substantial R&D within that industry alone. Yet oil was crucial for many canonical technologies of interest to both history of technology and innovation studies, including nuclear power, computing, biotechnology, nanotechnology, and scientific instrumentation. Technological activity within an oil economy/society bears that fuel’s mark. More generally, tracing oil and other energetic spillovers shows that different modes of energy production afford different modes of technological activity.