Establishing and running a National Forest Monitoring System (NFMS) is a complex task for governments. These systems serve to better inform forest-related decisions, thereby supporting the sustainable development of forests at national level. Their formulation requires a long-term vision and interdisciplinary collaboration, which is both a demanding and an exciting endeavour. These guidelines support this process by placing NFMS in the broader context of national forest-related decision processes and addressing a number of relevant strategic, operational and technical points. This publication includes good practice principles and incorporates a set of decision-support tools for planning and implementing a multipurpose NFMS, grounded in nationally appropriate and scientifically sound practices.