Regulatory enforcement is a core regulatory function and an important aspect of the regulatory oversight of nuclear facilities and activities. IAEA Safety Standards Series Nos. GSR Part I (Rev. 1) and GSG-13 provide requirements and recommendations for establishing and implementing enforcement policy. However, the lessons identified from various IAEA expert missions, peer reviews and regulatory conferences have revealed inconsistencies in the understanding, development and implementation of effective enforcement policies by regulatory bodies, highlighting the need for specific guidance on regulatory enforcement. The objective of this TECDOC is to assist regulatory bodies in developing and implementing an enforcement policy and process in line with the IAEA safety standards. It includes practical guidance from regulatory bodies with relevant experience and provides recommendations for enhancing enforcement actions in line with effectiveness, efficiency, and consistency. Additionally, it provides methods for evaluating the significance of non-compliances using a graded approach and applying the appropriate enforcement actions. This publication is intended for regulatory bodies, technical support organizations and competent authorities responsible for the oversight of nuclear facilities and activities.