The 21st century’s dynamic natural and social landscapes include increased wildfire fire intensity, unpredictable weather patterns, and demands for equity and justice. The very scale of these challenges requires new and creative approaches to land protection and stewardship; therefore, many conservation leaders and practitioners are exploring new ways to restore and care for the environment as integrated and interconnected landscapes. Landscape stewardship partnerships and networks have significantly grown over the past two decades to collaborate, innovate, and undertake collective action at varying scales. These adaptive cross-boundary partnerships and networks connect local communities, land- and water-managing agencies, private landowners, scientists, tribes, the non-profit sector, and many others to tackle the challenges we face. Because collaboration requires considerable trust and investment, stakeholders are seeking tools to understand its value and methods for measuring and monitoring its impact. However, there is a shortage of research-based frameworks to evaluate the impact of landscape stewardship partnerships practicing collaborative leadership. In this article, the Partnership Impact Model (a trademark of the Golden Gate National Parks Conservancy) is introduced as a promising impact assessment framework, with highlights from partnerships and networks that have used it. Readers are encouraged to consider this model to both monitor partnership health and to demonstrate its impact.