As a strategic tool, the impact of foresight on innovation performance is usually indirect, being realised by means of its effects on decisions about the overall innovation policy direction and other instruments. This chapter conceptualises the different ways in which foresight is used and reflects on the changing role of foresight over time. The heterogeneity of foresight contexts, rationales and applications is stressed. The experiences of a number of countries in Europe and worldwide which have undertaken national foresight activities related to innovation policy are reviewed. These show that foresight which specifically targets innovation policy can be designed to generate immediate impact on short-term decision making, and intermediate- and long-term impact through support for stakeholder learning and decision making on the direction of innovation. The more long-term these effects are, the harder they are to attribute. The impact of foresight on innovation policy depends on a clear understanding of the policy problem, on inclusion of the full variety of relevant key actors, on competent implementation teams, and on a transparent process and appropriate timing in the overall policy cycle.