As governments work to scale up new science, technology, and innovation (STI) approaches to accelerate sustainability transitions, policy experimentation is vital for testing what works and discontinuing what does not. This policy brief highlights practical examples of experimentation in action—such as regulatory sandboxes and randomised control trials—and offers key considerations for policymakers. Drawing on insights from the OECD’s Agenda for Transformative STI Policies, it emphasises how small-scale, deliberate interventions can foster innovation while managing risks, providing valuable guidance for shaping effective STI policies to achieve sustainability goals.