There is a growing societal awareness regarding the importance of regulatory systems for nuclear facilities and activities to have visible oversight of safety and security interfaces. This publication compiles relevant IAEA requirements, recommendations and guidance on identifying and addressing potential and actual interactions between nuclear safety and nuclear security systems and measures in nuclear power plants (NPPs). It also presents regulatory practices that are important to consider for nuclear safety and nuclear security, as they may reinforce or compromise the capacity of the regulatory bodies, competent authorities and operating organizations to meet nuclear safety and nuclear security requirements, including requirements relating to the interfaces between safety and security, during the application of regulatory functions in the various stages of the lifetime of an NPP.