Social impact assessment is a key challenge for enterprises in the social and solidarity economy (SSE), which place social and environmental goals at the heart of their actions. It can be used to analyse other forms of value creation that go beyond financial value alone, particularly contributions to ecological and social transition. This is not possible with con ventional business management tools that focus on purely economic factors. This assessment serves very different objectives. While it is often used to report activities to stake holders, it is also a strategic tool to better understand and explain an organisation’s social utility, motivate stakeholders, and more. It is crucial for all SSE enter prises to be able to grasp their impact in a structured way and make this dynamic a lasting part of their business model. But how to get started? How to find your way among all the methods and tools available? Which means and resources should you mobilise to achieve relevant results, while keeping operations running smoothly? Designed for leaders of organisations and their teams, as well as providers of assistance and f inance, this guide aims to throw light on challenges related to social impact assessment and provide the keys to adopting an approach that matches your situation. It sets out the essential steps and identifies organisational requirements. This guide also offers operational tools for each step and, finally, points to key resources and actors that can provide assistance for ESS enterprises along their assessment path.