In the two decades since the 1992 Rio Conference, land-use planning (LUP) has become recognized as a key instrument in putting discourses on sustainable development into practice. In Lao PDR, despite the implementation problems, it is still seen as a lever for securing land tenure, rationalizing extension services provision, and more recently, for implementing ‘Reduced Emissions from Deforestation and Forest Degradation' (REDD) schemes. Impact assessments of past LUP have revealed weaknesses of local institutions in the effective implementation of land policies. In order to avoid the blind trust placed in delusive LUP success stories, methods for monitoring community participation and understanding of LUP activities have been developed in order to assess the quality of the process. Expanding on this perspective, this article proposes a method to assess the quality of LUP outputs and to visualize the gap between planning objectives and their actual achievements. This method, based on a refined analysis of past and present land zoning practices in Lao PDR, gives full prominence to the complexity of landscape mosaics and the way local populations actually use the land. Furthermore, this approach, developed and tested under real planning conditions, can also be seen as a safeguard and support for inexperienced implementers in their land-use planning practices, as a diagnostic instrument for quality assessment, i.e. level of accuracy of a land-use plan, and may finally pave the way toward becoming a tool for land-use planning certification.