This thesis explores the emergence of transformative innovation policy, which can be understood as a reframing of the political agenda of innovation policy to address societal challenges such as climate change. This thesis conceptualises transformative innovation policy as an emerging policy paradigm, layered upon but not fully replacing earlier paradigms of Science & Technology Policy and Innovation Systems Policy. Grounded in argumentative discourse analysis, this thesis assesses the discourse institutionalisation of this emerging policy paradigm. The four empirical chapters focus on international policy organisations operating in a European context, namely the European Commission, Climate-KIC, the OECD and the European Environment Agency. The chapters are framed around three common questions, namely how transformative innovation policy is expressed in practice, to what extent it is institutionalised, and why events unfolded the way they did. The cases demonstrate that a paradigm shift in innovation policy is underway. There is a widespread recognition that existing ideas about innovation policy and its goals and instruments are failing to address current crises and that alternative solutions should be pursued. However, there is still much ambiguity about how exactly these new goals need to be addressed. This leads to clearly identifiable discursive struggles between broad and narrow articulations of transformative innovation policy. As a result, different directions of policy travel can be identified. This process is messy, and characteristic of the more evolutionary nature of policy change. The thesis also presents a closer assessment of the so-called ‘administrative battle of ideas’ representative of this broader paradigm shift. They display that organisational legacy and path dependency matter but that agency and path creation also play a crucial role. The presence of assumption surfacing and institutional entrepreneurship seem vital in achieving organisational change, which may well underlie any significant change in policy paradigm. This thesis contributes to knowledge by providing a conceptually and empirically informed framework to compare and contrast consecutive paradigms in innovation policy, and to identify and discuss different groups currently occupying this newly created discursive space. Furthermore, it makes some modest methodological and conceptual elaborations to the study of policy paradigms and policy paradigm change. In addition, this thesis shows that participant observation has potential to form a valuable contribution to STI policy studies.