This publication provides a summary of the International Conference on Effective Nuclear and Radiation Safety Regulatory Systems - Preparing for the Future in a Rapidly Changing Environment, including the opening and closing remarks, and summaries of all technical sessions and panels and summaries of side events. The conference served as a forum for identifying strategies to ensure regulatory resilience in a rapidly changing environment and to overcome life cycle challenges of nuclear installations and of activities involving radiation sources. It also focused on strengthening international cooperation and information sharing to improve regulatory effectiveness, agility and consistency in regulatory approaches related to new technologies. The major themes of the conference covered methodologies to increase public and stakeholder trust and regulatory credibility, best practices to sustain a competent workforce and develop the next generation of regulatory professionals and leaders, and programmes and strategies for the safe and secure use of radioactive material. This publication is intended for government ministers; senior officials and policymakers responsible for nuclear and radiation safety regulation; representatives of international, intergovernmental and non-governmental organizations (NGOs) with relevant competencies; regulatory bodies and other national competent authorities; and industry and other entities engaged in activities relevant to nuclear and radiation safety.