The knowledge economy is a dominant force in today's world, and innovation policy and national systems of innovation are central to it. In this article, we draw on different sociological and economic theories of risk to engage critically with innovation policy and national systems of innovation. Beck's understanding of a risk society, Schumpeter's innovation thesis, and Perez's techno-economic paradigm are used to consider the risk economy, and the broader risk implications of knowledge economy policies and their associated innovation systems. Derrida's theory of haunting provides the methodological framework for our discussion. We use his notion of "hauntology" to conceptualize the risk economy as a ghost that haunts knowledge economy policies and systems. The spectral risk economy draws attention to the inherent instability of the knowledge economy, and challenges the certainty of its economic dogma by offering an alternative perspective. The risk economy problematizes knowledge economy policies and systems by revealing the uncertain and "undecidable" future of social, political and cultural hazards ignored in the interest of commercial gain. (Contains 8 notes.)