We used participatory scenario planning to support strategic-level analysis by stakeholders in tourism and park management issues in Sagarmatha National Park, Nepal. Authority and responsibility for protected area management in Nepal are gradually being devolved to local communities. Tourism growth and globalization are strengthening the links between social-ecological change in mountain protected areas and drivers of change at national, regional, and global scales. Park management needs to become forward looking, and local communities need to increase their grasp of potential long-term changes and associated uncertainty. Scenario planning is a tool for dealing with long-term uncertainty and complexity and for guiding adaptive management. We developed scenarios together with representatives of the tourism industry, park comanagement institutions, and communities. Stakeholders described their understanding of the social-ecological system of the park. They formulated and tested 4 scenarios of system change, based on plausible changes in governance systems and the role of outside tourism industry actors. Stakeholders can use scenarios to reflect on the inherent uncertainty of long-term change, to address potentially conflictual issues by exploring multiple perspectives, and to assess the need to negotiate strategic goals and long-term visions for the park.