<p>Self-determination theory (SDT) has become a leading theory of motivation and wellness, and research in this area continues to grow each year. In this special issue we highlight a few recent and novel directions in SDT research, including its application to new areas such as compliance with laws and anti-racism, interdisciplinary interfaces with fields including philosophy and data science, and new methodological innovations applying computational modelling, databasing, economics, and neuroscience. We particularly highlight how SDT can be applied to socially complex issues outside the traditional scope of psychological research. We hope this special issue highlights both the narrow and broad implications and applications of the theory and the new directions it might take.</p>