Socio-technical systems in areas like energy, agrifood and mobility need to transform rapidly to become more sustainable and resilient. Science, technology and innovation (STI) have essential roles in these transformations, but governments must be more ambitious and act with greater urgency in their STI policies to meet these challenges. They should design policy portfolios that enable transformative innovation and new markets to emerge, challenge existing fossil-based systems, and create windows of opportunity for low-carbon technologies to break through. This calls for larger investments but also greater directionality in research and innovation, for example, through mission-oriented policies, to help direct and compress the innovation cycle for low-carbon technologies. International co-operation will be essential, but rising geopolitical tensions, including strategic competition in key emerging technologies, could make this difficult. OECD Science, Technology and Innovation Outlook 2023 explores these and other key issues and trends that present STI with a new operating environment to which it must adapt.