This guide presents the Landscape Governance Assessment Tool (LGAT) and the Decision Support System (DSS). It is intended for people addressing a variety of problems linked to forested landscapes, such as alleviating rural poverty, restoring degraded lands, meeting national climate commitments, or conserving biodiversity. The LGAT measures the strengths and weaknesses of governance in a forested landscape. Drawing on expert and stakeholder knowledge, the LGAT assesses the quality of governance and produces a summary rating, called the Landscape Governance Index (LGI). The tool can be used at many stages of a project, but it is primarily intended to provide an informed starting point for discussing and designing governance reforms. The DSS component creates a roadmap for reform by identifying priority areas, generating ideas for reform, and analyzing them to arrive at practical ways forward. Overall, the tool identifies reform pathways that have a good chance of making a difference in the landscape. The LGAT score demonstrates the need, while stakeholder and expert involvement in both the measurement and DSS steps shape and garner support for reforms. The DSS analysis screens the reforms to identify those likely to be practical and effective.