Abstract Scandinavian supreme courts have been described as deferential to the elected branches of government and reluctant to exercise their limited review powers. However, in recent years, these courts have increasingly decided cases impacting public policy making. Yet we lack comprehensive, comparative knowledge about the legal rules and judicial practices that govern the policymaking role of courts in Denmark, Norway, and Sweden. Addressing this gap, this article develops an analytical framework and systematically compares the evolving laws, rules, and practices that regulate the supreme courts’ constitutional review powers and court administration, the appointment and tenure of judges, access to the supreme courts, and their decision-making procedures over the last fifty years. The comparison reveals notable institutional differences across these judiciaries and finds that judicial expansion in Scandinavia has coincided with institutional changes that enhance judicial autonomy. This suggests that consequential reforms of domestic origin may have played a larger part in this development than previously appreciated.